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A366986
Square array T(n,k), n >= 1, k >= 0, read by antidiagonals downwards, where T(n,k) = Sum_{d|n} binomial(d+k-1,k).
0
1, 1, 2, 1, 3, 2, 1, 4, 4, 3, 1, 5, 7, 7, 2, 1, 6, 11, 14, 6, 4, 1, 7, 16, 25, 16, 12, 2, 1, 8, 22, 41, 36, 31, 8, 4, 1, 9, 29, 63, 71, 71, 29, 15, 3, 1, 10, 37, 92, 127, 147, 85, 50, 13, 4, 1, 11, 46, 129, 211, 280, 211, 145, 52, 18, 2, 1, 12, 56, 175, 331, 498, 463, 371, 176, 74, 12, 6
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
Columns k=0..5 give A000005, A000203, A007437, A059358, A073570, A101289.
T(n,n-1) gives A332508.
T(n,n) gives A343548.
Cf. A366977.
Sequence in context: A062001 A361043 A181847 * A209562 A259344 A239030
KEYWORD
nonn,tabl
AUTHOR
Seiichi Manyama, Oct 31 2023
STATUS
approved