A300549 a(n) = [x^n] Product_{d|n} (1 + x^d)/(1 - x^d).

1, 2, 4, 4, 10, 4, 28, 4, 36, 14, 44, 4, 284, 4, 60, 64, 202, 4, 616, 4, 732, 88, 92, 4, 5740, 22, 108, 112, 1404, 4, 10672, 4, 1828, 136, 140, 144, 42622, 4, 156, 160, 22940, 4, 28024, 4, 3420, 3172, 188, 4, 266524, 30, 4344, 208, 4764, 4, 58600, 224, 60204, 232, 236, 4, 3464272, 4, 252, 6052, 27338, 264

Offset

0,2

Links

Table of n, a(n) for n=0..65.

Index entries for sequences related to partitions

Formula

a(n) = 4 if n is a prime (A000040).

Mathematica

Table[SeriesCoefficient[Product[(1 + Boole[Mod[n, k] == 0] x^k)/(1 - Boole[Mod[n, k] == 0] x^k), {k, 1, n}], {x, 0, n}], {n, 0, 65}]

Crossrefs

Cf. A000040, A015128, A018818, A033630, A300547, A300548.

Sequence in context: A151712 A253827 A186987 * A038043 A126138 A366575

Adjacent sequences: A300546 A300547 A300548 * A300550 A300551 A300552

Keyword

nonn

Author

Ilya Gutkovskiy, Mar 08 2018

Status

approved