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%I #11 Mar 04 2020 01:49:04
%S 1,1104,170064,17051328,396408912,4634713440,34410979008,187471449984,
%T 814973040720,2975426026128,9486423324000,27053536131648,
%U 70485827477184,169930457503968,384164030001024
%N Theta series of Niemeier lattice of type D_24.
%D J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 407.
%H G. C. Greubel, <a href="/A008688/b008688.txt">Table of n, a(n) for n = 0..1000</a>
%t (* Coefficients 11/9 and -2/9 were computed from the data. *)
%t terms = 15; E4[q_] := 1 + 240 Sum[DivisorSigma[3, n]*q^(2 n), {n, 1, terms}]; E6[q_] := 1 - 504 Sum[DivisorSigma[5, n]*q^(2 n), {n, 1, terms}]; s = 11/9 E4[q]^3 - 2/9 E6[q]^2 + O[q]^(3 terms); Partition[ CoefficientList[s, q], 2][[All, 1]][[1 ;; terms]] (* _Jean-François Alcover_, Jul 06 2017 *)
%Y Cf. A008689 - A008704.
%K nonn
%O 0,2
%A _N. J. A. Sloane_
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