A300548 a(n) = [x^n] Product_{d|n} 1/(1 + x^d).

1, -1, 0, -2, 0, -2, 0, -2, 0, -5, 1, -2, 1, -2, 0, -14, 0, -2, 1, -2, 0, -18, 0, -2, 0, -7, 1, -23, 0, -2, 6, -2, 0, -26, 1, -26, 4, -2, 0, -30, 0, -2, 6, -2, 1, -286, 0, -2, 0, -9, 7, -38, 0, -2, 8, -38, 1, -42, 1, -2, 7, -2, 0, -493, 0, -44, 9, -2, 0, -50, 10, -2, 0, -2, 1, -698, 1, -50, 12, -2, 0, -239, 1, -2, 10, -56

Offset

0,4

Links

Antti Karttunen, Table of n, a(n) for n = 0..10201

Index entries for sequences related to partitions

Formula

a(n) = -2 if n is an odd prime (A065091).

Mathematica

Table[SeriesCoefficient[Product[1/(1 + Boole[Mod[n, k] == 0] x^k), {k, 1, n}], {x, 0, n}], {n, 0, 85}]

Prog

(PARI) A300548(n) = if(!n, 1, my(p=1); fordiv(n, d, p /= (1 + 'x^d)); polcoeff(Ser(p, 'x, 1+n), n)); \\ Antti Karttunen, Nov 27 2024

Crossrefs

Cf. A018818, A033630, A065091, A081362, A300547, A300549.

Sequence in context: A293516 A333808 A307692 * A293898 A368817 A324301

Adjacent sequences: A300545 A300546 A300547 * A300549 A300550 A300551

Keyword

sign

Author

Ilya Gutkovskiy, Mar 08 2018

Status

approved