Problem 52769. Easy Sequences 22: Sum of Proper Fractions
Let 'F' be the set of all proper fractions in lowest term, whose denominator is less than or equal 'd'. So, for d = 10, we have:
Note that '2/4' and '3/9' are not included because they are not in their lowest term, while '7/7' and '8/5' are not included because they are not proper fractions.
Write a function 'S(d)', which is the integer part of the sum of 'F(d)'. For the case above, the sum of elements of 'F(10)' is exactly '15.5'. Therefore S(10) = 15.
Solution Stats
Problem Comments
-
2 Comments
David Hill
on 23 Sep 2021
Could not figure out how to speed up my code. Ended up having to use a lookup table to speed it up sufficiently.
Ramon Villamangca
on 28 Sep 2021
Hi,
There is a shortcut using Mobius Inversion...
Solution Comments
Show commentsProblem Recent Solvers8
Suggested Problems
-
middleAsColumn: Return all but first and last element as a column vector
605 Solvers
-
Calculate Euler's phi function
91 Solvers
-
It's going down. We're finding simbers!
71 Solvers
-
46 Solvers
-
Lunar Arithmetic (Multiplication)
43 Solvers
More from this Author116
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!