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A007264
McKay-Thompson series of class 7A for Monster.
(Formerly M5302)
4
1, 0, 51, 204, 681, 1956, 5135, 12360, 28119, 60572, 125682, 251040, 487426, 920568, 1699611, 3070508, 5445510, 9490116, 16283793, 27537708, 45959775, 75760640, 123471327, 199081632, 317814988
OFFSET
-1,3
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
J. H. Conway and S. P. Norton, Monstrous Moonshine, Bull. Lond. Math. Soc. 11 (1979) 308-339.
N. D. Elkies, Elliptic and modular curves over finite fields and related computational issues, in AMS/IP Studies in Advanced Math., 7 (1998), 21-76, esp. p. 39.
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.
FORMULA
Expansion of (h+7)^2/h, where h = (eta(q)/eta(q^7))^4.
a(n) ~ exp(4*Pi*sqrt(n/7)) / (sqrt(2) * 7^(1/4) * n^(3/4)). - Vaclav Kotesovec, Dec 04 2015
EXAMPLE
T7A = 1/q + 51*q + 204*q^2 + 681*q^3 + 1956*q^4 + 5135*q^5 + 12360*q^6 + ...
MATHEMATICA
QP = QPochhammer; h = q*(QP[q^7]/QP[q])^4; s = 1 - 10*q + q*((1+7*h)^2/h - 1/q) + O[q]^30; CoefficientList[s, q] (* Jean-François Alcover, Nov 15 2015 *)
PROG
(PARI) q='q+O('q^50); F =(eta(q)/eta(q^7))^4/q; Vec(F*(1 + 7/F)^2 - 10) \\ G. C. Greubel, May 10 2018
CROSSREFS
Essentially same as A045489 and A030183.
Sequence in context: A031431 A157365 A157916 * A158640 A107253 A030535
KEYWORD
nonn
STATUS
approved