OFFSET
-1,3
LINKS
G. C. Greubel, 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
Expansion of -6 + (1 + 3*F)^2* (1/F + 1 + 3*F) where F = eta(q^3)* eta(q^33)/ (eta(q)* eta(q^11)) in powers of q.
G.f. is Fourier series of a level 11 modular function. f(-1 / (11t)) = f(t) where q = exp(2 Pi i t).
a(n) ~ exp(4*Pi*sqrt(n/11)) / (sqrt(2)*11^(1/4)*n^(3/4)). - Vaclav Kotesovec, Sep 07 2017
EXAMPLE
T11A = 1/q + 17*q + 46*q^2 + 116*q^3 + 252*q^4 + 533*q^5 + 1034*q^6 + ...
MATHEMATICA
QP = QPochhammer; F = q*QP[q^3]*(QP[q^33]/(QP[q]*QP[q^11])); s = q*(-6 + (1 + 3*F)^2*(1/F + 1 + 3*F)) + O[q]^40; CoefficientList[s, q] (* Jean-François Alcover, Nov 15 2015 *)
PROG
(PARI) q='q+O('q^30); {F = q*(eta(q^3)*eta(q^33)/(eta(q)*eta(q^11)))}; Vec(-6 + (1+3*F)^2*(3*F + 1 +1/F)) \\ G. C. Greubel, May 28 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 27 2000
STATUS
approved