OFFSET
0,2
COMMENTS
Essentially the same as A058666. - R. J. Mathar, Mar 23 2012
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..2500
D. Ford, J. McKay and S. P. Norton, More on replicable functions, Comm. Algebra 22, No. 13, 5175-5193 (1994).
FORMULA
Expansion of A + 2*q/A, where A = q^(1/2)*(eta(q^2)*eta(q^10)/( eta(q^4)* eta(q^20))), in powers of q. - G. C. Greubel, Jun 26 2018
EXAMPLE
T40c = 1/q +2*q -q^3 +2*q^5 +2*q^9 -q^11 +4*q^13 +q^15 +4*q^17 +...
MATHEMATICA
eta[q_] := q^(1/24)*QPochhammer[q]; A:= q^(1/2)*(eta[q^2]*eta[q^10]/( eta[q^4]*eta[q^20])); a := CoefficientList[Series[A + 2*q/A, {q, 0, 60}], q]; Table[a[[n]], {n, 1, 50}] (* G. C. Greubel, Jun 26 2018 *)
PROG
(PARI) q='q+O('q^50); A = (eta(q^2)*eta(q^10)/(eta(q^4)*eta(q^20))); Vec(A + 2*q/A) \\ G. C. Greubel, Jun 26 2018
CROSSREFS
KEYWORD
sign
AUTHOR
Michael Somos, Aug 28 2005
STATUS
approved