OFFSET
1,6
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1275 (first 50 antidiagonals)
FORMULA
G.f. of column k: Sum_{j>=1} j^k*x^j/(1 + x^j).
EXAMPLE
Square array begins:
1, 1, 1, 1, 1, 1, ...
0, 1, 3, 7, 15, 31, ...
2, 4, 10, 28, 82, 244, ...
-1, 1, 11, 55, 239, 991, ...
2, 6, 26, 126, 626, 3126, ...
0, 4, 30, 196, 1230, 7564, ...
MATHEMATICA
Table[Function[k, Sum[(-1)^(n/d + 1) d^k, {d, Divisors[n]}]][i - n], {i, 0, 12}, {n, 1, i}] // Flatten
Table[Function[k, SeriesCoefficient[Sum[j^k x^j/(1 + x^j), {j, 1, n}], {x, 0, n}]][i - n], {i, 0, 12}, {n, 1, i}] // Flatten
PROG
(PARI) T(n, k)={sumdiv(n, d, (-1)^(n/d+1)*d^k)}
for(n=1, 10, for(k=0, 8, print1(T(n, k), ", ")); print); \\ Andrew Howroyd, Nov 26 2018
CROSSREFS
KEYWORD
sign,tabl
AUTHOR
Ilya Gutkovskiy, Nov 26 2018
STATUS
approved