Problem 42763. Fill the Matrix - 2

Input is a column vector and n.

n columns will be added to the left of the input column. The first value of the row is the mean of the previous row. The matrix should be filled as follows.

 input matrix = [1:8]'
 n = 4;
 output = 
 [
 0      0      0      0      1
 0.2    0      0      0      2
 0.44   0.2    0      0      3
 0.7280 0.44   0.2    0      4
 1.0736 0.7280 0.44   0.2    5
 1.4883 1.0736 0.7280 0.44   6
 1.9460 1.4883 1.0736 0.7280 7
 2.4472 1.9460 1.4883 1.0736 8
 ];

I request you to use the mean( ) function.