OFFSET
-1,7
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).
David A. Madore, Coefficients of Moonshine (McKay-Thompson) series, The Math Forum
FORMULA
Expansion of B + 1 + 1/B, where B = eta(q)*eta(q^6)*eta(q^26)*eta(q^39)/( eta(q^2)*eta(q^3)*eta(q^13)*eta(q^78)), in powers of q. - G. C. Greubel, Jun 30 2018
a(n) ~ exp(2*Pi*sqrt(2*n/39)) / (2^(3/4) * 39^(1/4) * n^(3/4)). - Vaclav Kotesovec, Jul 02 2018
EXAMPLE
T78A = 1/q + q + q^2 + q^3 + 2*q^5 + q^6 + 3*q^7 + 3*q^8 + 3*q^9 + 2*q^10 + ...
MATHEMATICA
eta[q_] := q^(1/24)*QPochhammer[q]; B:= eta[q]*eta[q^6]*eta[q^26]* eta[q^39]/(eta[q^2]*eta[q^3]*eta[q^13]*eta[q^78]); a:= CoefficientList[ Series[1 + B + 1/B, {q, 0, 60}], q]; Table[[[n]], {n, 1, 50}] (* G. C. Greubel, Jun 30 2018 *)
PROG
(PARI) q='q+O('q^50); B = eta(q)*eta(q^6)*eta(q^26)*eta(q^39)/(q*eta(q^2) *eta(q^3)*eta(q^13)*eta(q^78)); Vec(B + 1 + 1/B) \\ G. C. Greubel, Jun 30 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 27 2000
EXTENSIONS
More terms from Michel Marcus, Feb 24 2014
STATUS
approved