OFFSET
-1,2
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, Comm. Algebra 22, No. 13, 5175-5193 (1994).
FORMULA
Expansion of A - 7*q/A, where A = q^(1/2)*(eta(q)/eta(q^7))^2, in powers of q. - G. C. Greubel, Jun 20 2018
a(n) ~ -exp(2*Pi*sqrt(2*n/7)) / (2^(3/4) * 7^(1/4) * n^(3/4)). - Vaclav Kotesovec, Jun 29 2018
EXAMPLE
T14a = 1/q - 9*q - 15*q^3 - 33*q^5 - 69*q^7 - 138*q^9 - 254*q^11 - ...
MATHEMATICA
eta[q_]:= q^(1/24)*QPochhammer[q]; A:= q^(1/2)*(eta[q]/eta[q^7])^2; a:= CoefficientList[Series[A - 7*q/A, {q, 0, 60}], q]; Table[a[[n]], {n, 0, 50}] (* G. C. Greubel, Jun 20 2018 *)
PROG
(PARI) q='q+O('q^50); A = (eta(q)/eta(q^7))^2; Vec(A - 7*q/A) \\ G. C. Greubel, Jun 20 2018
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Nov 27 2000
EXTENSIONS
Terms a(12) onward added by G. C. Greubel, Jun 20 2018
STATUS
approved