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A127570
Triangle T(n,k) = sigma(k) if k|n, otherwise T(n,k)=0; 1 <= k <= n.
0
1, 1, 3, 1, 0, 4, 1, 3, 0, 7, 1, 0, 0, 0, 6, 1, 3, 4, 0, 0, 12, 1, 0, 0, 0, 0, 0, 8, 1, 3, 0, 7, 0, 0, 0, 15, 1, 0, 4, 0, 0, 0, 0, 0, 13, 1, 3, 0, 0, 6, 0, 0, 0, 0, 18, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12, 1, 3, 4, 7, 0, 12, 0, 0, 0, 0, 0, 28, 1
OFFSET
1,3
FORMULA
T(n,k) = Sum_{j=k..n} A051731(n,j)*A130208(j,k) = A051731(n,k)*A000203(k).
EXAMPLE
First few rows of the triangle are:
1;
1, 3;
1, 0, 4;
1, 3, 0, 7;
1, 0, 0, 0, 6;
1, 3, 4, 0, 0, 12;
...
CROSSREFS
Cf. A000203 (sigma, diagonal n=k), A007429 (row sums), A051731.
Sequence in context: A346369 A127569 A117372 * A340583 A292506 A212186
KEYWORD
nonn,tabl,easy
AUTHOR
Gary W. Adamson, Jan 19 2007
STATUS
approved