A127572 Triangle, T(n,k) = sigma(k) * n/k if k|n, T(n,k) = 0 otherwise.

1, 2, 3, 3, 0, 4, 4, 6, 0, 7, 5, 0, 0, 0, 6, 6, 9, 8, 0, 0, 12, 7, 0, 0, 0, 0, 0, 8, 8, 12, 0, 14, 0, 0, 0, 15, 9, 0, 12, 0, 0, 0, 0, 0, 13, 10, 15, 0, 0, 12, 0, 0, 0, 0, 18

Offset

1,2

Links

Table of n, a(n) for n=1..55.

Formula

A126988 * M, where M = an infinite matrix with sigma(n) in the main diagonal and the rest zeros.

Example

First few rows of the triangle are:
1;
2, 3;
3, 0, 4;
4, 6, 0, 7;
5, 0, 0, 0, 6;
6, 9, 8, 0, 0, 12;
...

Crossrefs

Main diagonal = sigma(n), A000203; row sums = A060640.

Cf. A126988.

Sequence in context: A192498 A360665 A308178 * A021815 A238525 A359788

Adjacent sequences: A127569 A127570 A127571 * A127573 A127574 A127575

Keyword

nonn,tabl

Author

Gary W. Adamson, Jan 19 2007

Extensions

Edited by Franklin T. Adams-Watters, Aug 24 2011

Status

approved