A127470 Triangle equal to the matrix product A127466 * A051731.
1, 4, 2, 9, 0, 6, 16, 12, 0, 8, 25, 0, 0, 0, 20, 36, 18, 24, 0, 0, 12, 49, 0, 0, 0, 0, 0, 42, 64, 56, 0, 48, 0, 0, 0, 32, 81, 0, 72, 0, 0, 0, 0, 0, 54, 100, 50, 0, 0, 80, 0, 0, 0, 0, 40, 121, 0, 0, 0, 0, 0, 0, 0, 0, 0, 110, 144, 108, 96, 72, 0, 72, 0, 0, 0, 0, 0, 48
Offset: 1
Examples
First few rows of the triangle are: 1; 4, 2; 9, 0, 6; 16, 12, 0, 8; 25, 0, 0, 0, 20; 36, 18, 24, 0, 0, 12; 49, 0, 0, 0, 0, 0, 42; 64, 56, 0, 48, 0, 0, 0, 32; 81, 0, 72, 0, 0, 0, 0, 0, 54; ...
Programs
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Maple
A127470 := proc(n,k) add( A127466(n,j)*A051731(j,k),j=k..n) ; end proc: # R. J. Mathar, Sep 08 2013
Formula
T(n,1) = n^2.
T(n,n) = n*phi(n) = A002618(n).
Extensions
Terms corrected by R. J. Mathar, Sep 08 2013