OFFSET
-1,3
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = -1..1000
J. H. Conway and S. P. Norton, Monstrous Moonshine, Bull. Lond. Math. Soc. 11 (1979) 308-339.
D. Ford, J. McKay and S. P. Norton, More on replicable functions, Commun. Algebra 22, No. 13, 5175-5193 (1994).
J. McKay and H. Strauss, The q-series of monstrous moonshine and the decomposition of the head characters, Comm. Algebra 18 (1990), no. 1, 253-278.
Wikipedia, Generalized Monstrous Moonshine
FORMULA
a(n) = A121665(n) + A226235(n) = A121666(n) + 64*A123653(n) = A121667(n) + 81*A284607(n) for n > 0. - Seiichi Manyama, Mar 30 2017
a(n) ~ exp(2*Pi*sqrt(2*n/3)) / (2^(3/4) * 3^(1/4) * n^(3/4)). - Vaclav Kotesovec, Mar 30 2017
EXAMPLE
T6A = 1/q + 79*q + 352*q^2 + 1431*q^3 + 4160*q^4 + 13015*q^5 + 31968*q^6 + ...
MATHEMATICA
nmax = 50; Flatten[{1, 0, Rest[Rest[CoefficientList[Series[Product[((1 + x^k)/(1 + x^(3*k)))^12, {k, 1, nmax}] + x^2*Product[((1 + x^(3*k))/(1 + x^k))^12, {k, 1, nmax}], {x, 0, nmax}], x]]]}] (* Vaclav Kotesovec, Mar 30 2017 *)
eta[q_] := q^(1/24)*QPochhammer[q]; e6B:= (eta[q^2]*eta[q^3]/(eta[q]* eta[q^6]))^12; a:= CoefficientList[Series[q*(e6B - 12 + 1/e6B), {q, 0, 50}], q]; Table[a[[n]], {n, 1, 50}] (*G. C. Greubel, May 10 2018 *)
PROG
(PARI) q='q+O('q^50); F =(eta(q^2)*eta(q^3)/(eta(q)*eta(q^6)))^12/q; Vec(F -12 +1/F) \\ G. C. Greubel, May 10 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved