A321302 Expansion of Product_{i>=1, j>=1, k>=1, l>=1} (1 - x^(i*j*k*l))/(1 + x^(i*j*k*l)).

1, -2, -6, 6, 14, 30, -14, -98, -86, -150, 282, 486, 502, 670, -1118, -1226, -4396, -3814, 1326, 3834, 20354, 16330, 18334, -6606, -45658, -60762, -121770, -60122, -22750, 160314, 303638, 435450, 542336, 162782, -45830, -1090994, -1576378, -2608146, -2408142, -988202, 479834

Offset

0,2

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Formula

G.f.: Product_{k>=1} ((1 - x^k)/(1 + x^k))^A007426(k).

Prog

(PARI) \\ here b(n) is A007426.
b(n)={vecprod(apply(e->binomial(e+3, 3), factor(n)[, 2]))}
seq(n)={Vec(prod(k=1, n, ((1 - x^k)/(1 + x^k) + O(x*x^n))^b(k)))} \\ Andrew Howroyd, Nov 06 2018

Crossrefs

Convolution inverse of A321240.

Cf. A007426, A320908, A321241.

Sequence in context: A073131 A206490 A343315 * A294735 A367072 A251548

Adjacent sequences: A321299 A321300 A321301 * A321303 A321304 A321305

Keyword

sign

Author

Seiichi Manyama, Nov 03 2018

Status

approved