OFFSET
-1,6
LINKS
Seiichi Manyama, Table of n, a(n) for n = -1..10000
D. Ford, J. McKay and S. P. Norton, More on replicable functions, Commun. Algebra 22, No. 13, 5175-5193 (1994).
FORMULA
Expansion of 1 + eta(q)*eta(q^3)/(eta(q^7)*eta(q^21)) in powers of q. - G. C. Greubel, Jun 14 2018
EXAMPLE
T21B = 1/q - q - q^2 + q^3 + 2*q^4 - q^5 + 3*q^6 - q^7 - q^8 - 2*q^9 + q^11 - ...
MATHEMATICA
eta[q_]:= q^(1/24)*QPochhammer[q]; a:= CoefficientList[Series[q*(1 + (eta[q]*eta[q^3]/(eta[q^7]*eta[q^21]))), {q, 0, 60}], q]; Table[a[[n]], {n, 1, 70}] (* G. C. Greubel, Jun 14 2018 *)
PROG
(PARI) q='q+O('q^70); A = 1 + eta(q)*eta(q^3)/(eta(q^7)*eta(q^21))/q; Vec(A) \\ G. C. Greubel, Jun 14 2018
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Nov 27 2000
EXTENSIONS
More terms from Michel Marcus, Feb 18 2014
STATUS
approved