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%I #19 Jun 28 2018 04:19:42
%S 1,1,5,5,11,10,26,25,46,55,91,101,156,181,272,316,457,531,747,862,
%T 1188,1387,1858,2177,2864,3348,4334,5078,6485,7589,9605,11215,14026,
%U 16365,20308,23656,29094,33876,41359,48068,58266,67645,81537,94476,113269,131052,156311,180518
%N McKay-Thompson series of class 28a for Monster.
%H G. C. Greubel, <a href="/A058610/b058610.txt">Table of n, a(n) for n = -1..2500</a>
%H D. Ford, J. McKay and S. P. Norton, <a href="http://dx.doi.org/10.1080/00927879408825127">More on replicable functions</a>, Comm. Algebra 22, No. 13, 5175-5193 (1994).
%H <a href="/index/Mat#McKay_Thompson">Index entries for McKay-Thompson series for Monster simple group</a>
%F Expansion of A - q/A, where A = q^(1/2)*(eta(q^2)*eta(q^7)/(eta(q)* eta(q^14)))^2, in powers of q. - _G. C. Greubel_, Jun 22 2018
%F a(n) ~ exp(2*Pi*sqrt(n/7)) / (2 * 7^(1/4) * n^(3/4)). - _Vaclav Kotesovec_, Jun 28 2018
%e T28a = 1/q + q + 5*q^3 + 5*q^5 + 11*q^7 + 10*q^9 + 26*q^11 + 25*q^13 + ...
%t eta[q_] := q^(1/24)*QPochhammer[q]; A := q^(1/2)*(eta[q^2]*eta[q^7]/(eta[q]*eta[q^14]))^2; a:= CoefficientList[Series[(A - q/A), {q, 0, 100}], q]; Table[a[[n]], {n, 1, 70}] (* _G. C. Greubel_, Jun 22 2018 *)
%o (PARI) q='q+O('q^50); A = (eta(q^2)*eta(q^7)/(eta(q)*eta(q^14)))^2; Vec(A - q/A) \\ _G. C. Greubel_, Jun 22 2018
%Y Cf. A000521, A007240, A014708, A007241, A007267, A045478, etc.
%K nonn
%O -1,3
%A _N. J. A. Sloane_, Nov 27 2000
%E Terms a(12) onward added by _G. C. Greubel_, Jun 22 2018