A127651 Triangle T(n,k) = n*k if k|n, 0 otherwise; 1<=k<=n.

1, 2, 4, 3, 0, 9, 4, 8, 0, 16, 5, 0, 0, 0, 25, 6, 12, 18, 0, 0, 36, 7, 0, 0, 0, 0, 0, 49, 8, 16, 0, 32, 0, 0, 0, 64, 9, 0, 27, 0, 0, 0, 0, 0, 81, 10, 20, 0, 0, 50, 0, 0, 0, 0, 100, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 121, 12, 24, 36, 48, 0, 72, 0, 0, 0, 0, 0, 144

Offset

1,2

Comments

Equals the matrix product A127648 * A127093 as infinite lower triangular matrices.

Links

Table of n, a(n) for n=1..78.

Formula

T(n,k) = n*A127093(n,k). - R. J. Mathar, Oct 01 2011

Example

First few rows of the triangle are:
1;
2, 4;
3, 0, 9;
4, 8, 0, 16;
5, 0, 0, 0, 25;
6, 12, 18, 0, 0, 36;
7, 0, 0, 0, 0, 0, 49;
8, 16, 0, 32, 0, 0, 0, 64;
...

Maple

A127651 := proc(n, k)
        if n mod k =0 then
                n*k;
        else
                0 ;
        end if;
end proc: # R. J. Mathar, Oct 01 2011

Crossrefs

Cf. A127648, A127093, A064987 (row sums).

Sequence in context: A246713 A106137 A213381 * A019641 A085008 A285587

Adjacent sequences: A127648 A127649 A127650 * A127652 A127653 A127654

Keyword

nonn,tabl,easy

Author

Gary W. Adamson, Jan 22 2007

Status

approved