A305320 Expansion of Product_{k>=1} (1 - x^sigma(k)).

1, -1, 0, -1, 0, 1, -1, 1, -1, 2, 1, 0, -3, 0, 0, 2, 1, -2, 0, 1, 2, -1, -3, -4, 0, 3, 4, 0, -4, -1, 6, -3, 3, -9, 0, 5, 10, 0, -6, -7, 0, 6, -2, 2, -9, 6, 7, 4, -7, -7, -11, 8, 11, 3, -5, -1, -3, 9, -10, 1, -9, 0, 16, 8, 0, -4, -4, -20, 12, -8, 11, 0, -7, 14, -2

Offset: 0

Author

Seiichi Manyama, May 30 2018

Keywords

• sign

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A000203, A111865, A305321.

Programs

Maple

with(numtheory):
seq(coeff(series(mul(1-x^sigma(k),k=1..n), x,90),x,n),n=0..80); # Muniru A Asiru, May 31 2018

PARI

N=99; x='x+O('x^N); Vec(prod(k=1, N, 1-x^sigma(k)))