A030215 Expansion of eta(q^9)*eta(q^15).

0, 1, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, -1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, -1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0

Offset: 0

Author

N. J. A. Sloane

Keywords

• sign

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..10000
• M. Koike, On McKay's conjecture, Nagoya Math. J., 95 (1984), 85-89.

Crossrefs

Cf. Expansion of eta(q^k)*eta(q^(24 - k)): A030199 (k=1), A030201 (k=3), A030213 (k=5), A030214 (k=7), this sequence (k=9), A030216 (k=10), A030217 (k=11).

Programs

Mathematica

eta = QPochhammer;
CoefficientList[q eta[q^9] eta[q^15] + O[q]^100, q] (* Jean-François Alcover, Feb 21 2021 *)

Formula

Expansion of x * Product_{k>=1} (1 - x^(9*k)) * (1 - x^(15*k)). - Seiichi Manyama, Oct 18 2016