OFFSET
-1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = -1..2500
D. Ford, J. McKay and S. P. Norton, More on replicable functions, Comm. Algebra 22, No. 13, 5175-5193 (1994).
FORMULA
Expansion of q^(1/2)*(eta(q)/eta(q^7))^2 in powers of q. - G. C. Greubel, Jun 20 2018
EXAMPLE
T14b = 1/q - 2*q - q^3 + 2*q^5 + q^7 + 2*q^9 - 2*q^11 + 2*q^13 - 6*q^15 - ...
MATHEMATICA
QP = QPochhammer; s = (QP[q]/QP[q^7])^2 + O[q]^80; CoefficientList[s, q] (* Georg Fischer, Nov 14 2020 *)
PROG
(PARI) q='q+O('q^70); Vec((eta(q)/eta(q^7))^2) \\ 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