OFFSET
1,3
FORMULA
G.f. of column k: Sum_{j>=1} x^j/(1 - x^j)^(k+1).
EXAMPLE
Square array begins:
1, 1, 1, 1, 1, 1, 1, ...
2, 3, 4, 5, 6, 7, 8, ...
2, 4, 7, 11, 16, 22, 29, ...
3, 7, 14, 25, 41, 63, 92, ...
2, 6, 16, 36, 71, 127, 211, ...
4, 12, 31, 71, 147, 280, 498, ...
2, 8, 29, 85, 211, 463, 925, ...
PROG
(PARI) T(n, k) = sumdiv(n, d, binomial(d+k-1, k));
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Seiichi Manyama, Oct 31 2023
STATUS
approved