{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-05-26T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":44341,"title":"Hexagonal numbers on a spiral matrix","description":"Put hexagonal numbers in a ( m x m ) spiral matrix and return the sum of its diagonal elements.\r\n\r\nFormula of hexagonal numbers h(n) = 2n^2 - n\r\n\r\nIf m = 5;\r\n\r\n  spiral(5) =   \r\n    21    22    23    24    25\r\n    20     7     8     9    10\r\n    19     6     1     2    11\r\n    18     5     4     3    12\r\n    17    16    15    14    13\r\n\r\nFirst 5x5=25 hexagonal numbers are;\r\n\r\n  h = [1 6 15 28 45 66 91 120 153 190 231 276 325 378 435 496 561 630 703 780 861 946 1035 1128 1225]\r\n\r\nWe put them in a spiral format;\r\n\r\n   spiralHex = [\r\n861\t946\t1035\t1128\t1225\r\n780\t91\t120\t153\t190\r\n703\t66\t1\t6\t231\r\n630\t45\t28\t15\t276\r\n561\t496\t435\t378\t325\r\n\r\nAnd sum its diag = 861 + 91 + 1 + 15 + 325 = 1293.\r\n\r\nReturn the output as char.","description_html":"\u003cp\u003ePut hexagonal numbers in a ( m x m ) spiral matrix and return the sum of its diagonal elements.\u003c/p\u003e\u003cp\u003eFormula of hexagonal numbers h(n) = 2n^2 - n\u003c/p\u003e\u003cp\u003eIf m = 5;\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003espiral(5) =   \r\n  21    22    23    24    25\r\n  20     7     8     9    10\r\n  19     6     1     2    11\r\n  18     5     4     3    12\r\n  17    16    15    14    13\r\n\u003c/pre\u003e\u003cp\u003eFirst 5x5=25 hexagonal numbers are;\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003eh = [1 6 15 28 45 66 91 120 153 190 231 276 325 378 435 496 561 630 703 780 861 946 1035 1128 1225]\r\n\u003c/pre\u003e\u003cp\u003eWe put them in a spiral format;\u003c/p\u003e\u003cpre\u003e   spiralHex = [\r\n861\t946\t1035\t1128\t1225\r\n780\t91\t120\t153\t190\r\n703\t66\t1\t6\t231\r\n630\t45\t28\t15\t276\r\n561\t496\t435\t378\t325\u003c/pre\u003e\u003cp\u003eAnd sum its diag = 861 + 91 + 1 + 15 + 325 = 1293.\u003c/p\u003e\u003cp\u003eReturn the output as char.\u003c/p\u003e","function_template":"function y = hexagonalSpiral(m)\r\n  \r\nend","test_suite":"%%\r\nm = 1;\r\ny_correct = '1';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 2;\r\ny_correct = '16';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 5;\r\ny_correct = '1293';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 16;\r\ny_correct = '420800';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 100;\r\ny_correct = '4000333360';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 1295;\r\ny_correct = '1456830580539887';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 2500;\r\ny_correct = '39062505208334000';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 5000;\r\ny_correct = '1250000041666668000';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 8000;\r\ny_correct = '13107200170666668800';\r\nassert(isequal(hexagonalSpiral(m),y_correct))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":8703,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":164,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":35,"created_at":"2017-09-19T08:06:36.000Z","updated_at":"2026-04-18T10:55:17.000Z","published_at":"2017-10-16T01:50:59.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003ePut hexagonal numbers in a ( m x m ) spiral matrix and return the sum of its diagonal elements.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFormula of hexagonal numbers h(n) = 2n^2 - n\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eIf m = 5;\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[spiral(5) =   \\n  21    22    23    24    25\\n  20     7     8     9    10\\n  19     6     1     2    11\\n  18     5     4     3    12\\n  17    16    15    14    13]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFirst 5x5=25 hexagonal numbers are;\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[h = [1 6 15 28 45 66 91 120 153 190 231 276 325 378 435 496 561 630 703 780 861 946 1035 1128 1225]]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWe put them in a spiral format;\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[   spiralHex = [\\n861  946  1035  1128  1225\\n780  91  120  153  190\\n703  66  1  6  231\\n630  45  28  15  276\\n561  496  435  378  325]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eAnd sum its diag = 861 + 91 + 1 + 15 + 325 = 1293.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eReturn the output as char.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"problems":[{"id":44341,"title":"Hexagonal numbers on a spiral matrix","description":"Put hexagonal numbers in a ( m x m ) spiral matrix and return the sum of its diagonal elements.\r\n\r\nFormula of hexagonal numbers h(n) = 2n^2 - n\r\n\r\nIf m = 5;\r\n\r\n  spiral(5) =   \r\n    21    22    23    24    25\r\n    20     7     8     9    10\r\n    19     6     1     2    11\r\n    18     5     4     3    12\r\n    17    16    15    14    13\r\n\r\nFirst 5x5=25 hexagonal numbers are;\r\n\r\n  h = [1 6 15 28 45 66 91 120 153 190 231 276 325 378 435 496 561 630 703 780 861 946 1035 1128 1225]\r\n\r\nWe put them in a spiral format;\r\n\r\n   spiralHex = [\r\n861\t946\t1035\t1128\t1225\r\n780\t91\t120\t153\t190\r\n703\t66\t1\t6\t231\r\n630\t45\t28\t15\t276\r\n561\t496\t435\t378\t325\r\n\r\nAnd sum its diag = 861 + 91 + 1 + 15 + 325 = 1293.\r\n\r\nReturn the output as char.","description_html":"\u003cp\u003ePut hexagonal numbers in a ( m x m ) spiral matrix and return the sum of its diagonal elements.\u003c/p\u003e\u003cp\u003eFormula of hexagonal numbers h(n) = 2n^2 - n\u003c/p\u003e\u003cp\u003eIf m = 5;\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003espiral(5) =   \r\n  21    22    23    24    25\r\n  20     7     8     9    10\r\n  19     6     1     2    11\r\n  18     5     4     3    12\r\n  17    16    15    14    13\r\n\u003c/pre\u003e\u003cp\u003eFirst 5x5=25 hexagonal numbers are;\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003eh = [1 6 15 28 45 66 91 120 153 190 231 276 325 378 435 496 561 630 703 780 861 946 1035 1128 1225]\r\n\u003c/pre\u003e\u003cp\u003eWe put them in a spiral format;\u003c/p\u003e\u003cpre\u003e   spiralHex = [\r\n861\t946\t1035\t1128\t1225\r\n780\t91\t120\t153\t190\r\n703\t66\t1\t6\t231\r\n630\t45\t28\t15\t276\r\n561\t496\t435\t378\t325\u003c/pre\u003e\u003cp\u003eAnd sum its diag = 861 + 91 + 1 + 15 + 325 = 1293.\u003c/p\u003e\u003cp\u003eReturn the output as char.\u003c/p\u003e","function_template":"function y = hexagonalSpiral(m)\r\n  \r\nend","test_suite":"%%\r\nm = 1;\r\ny_correct = '1';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 2;\r\ny_correct = '16';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 5;\r\ny_correct = '1293';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 16;\r\ny_correct = '420800';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 100;\r\ny_correct = '4000333360';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 1295;\r\ny_correct = '1456830580539887';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 2500;\r\ny_correct = '39062505208334000';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 5000;\r\ny_correct = '1250000041666668000';\r\nassert(isequal(hexagonalSpiral(m),y_correct))\r\n\r\n%%\r\nm = 8000;\r\ny_correct = '13107200170666668800';\r\nassert(isequal(hexagonalSpiral(m),y_correct))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":8703,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":164,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":35,"created_at":"2017-09-19T08:06:36.000Z","updated_at":"2026-04-18T10:55:17.000Z","published_at":"2017-10-16T01:50:59.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003ePut hexagonal numbers in a ( m x m ) spiral matrix and return the sum of its diagonal elements.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFormula of hexagonal numbers h(n) = 2n^2 - n\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eIf m = 5;\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[spiral(5) =   \\n  21    22    23    24    25\\n  20     7     8     9    10\\n  19     6     1     2    11\\n  18     5     4     3    12\\n  17    16    15    14    13]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFirst 5x5=25 hexagonal numbers are;\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[h = [1 6 15 28 45 66 91 120 153 190 231 276 325 378 435 496 561 630 703 780 861 946 1035 1128 1225]]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWe put them in a spiral format;\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[   spiralHex = [\\n861  946  1035  1128  1225\\n780  91  120  153  190\\n703  66  1  6  231\\n630  45  28  15  276\\n561  496  435  378  325]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eAnd sum its diag = 861 + 91 + 1 + 15 + 325 = 1293.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eReturn the output as char.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"errors":[],"facets":[[{"value":"Big Numbers","count":1,"selected":false},{"value":"Cody5:Hard","count":1,"selected":false}],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"spiral matrix\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}