OFFSET
-1,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = -1..1000
D. Ford, J. McKay and S. P. Norton, More on replicable functions, Commun. Algebra 22, No. 13, 5175-5193 (1994).
FORMULA
a(n) ~ exp(4*Pi*sqrt(n/15)) / (sqrt(2) * 15^(1/4) * n^(3/4)). - Vaclav Kotesovec, Sep 07 2017
EXAMPLE
T15A = 1/q + 8*q + 22*q^2 + 42*q^3 + 70*q^4 + 155*q^5 + 246*q^6 + 421*q^7 + ...
MATHEMATICA
QP = QPochhammer; A = QP[q]*(QP[q^5]/(QP[q^3]*QP[q^15])); s = -4q + (A + 3*(q/A))^2 + O[q]^40; CoefficientList[s, q] (* Jean-François Alcover, Nov 16 2015, adapted from A153765 *)
PROG
(PARI) q='q+O('q^30); F= (eta(q)*eta(q^5)/(eta(q^3)*eta(q^15)))^2; Vec(2*q + F + 9*q^2/F) \\ G. C. Greubel, Jun 03 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 27 2000
EXTENSIONS
More terms from Michel Marcus, Feb 19 2014
STATUS
approved