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%I #8 Jul 14 2021 03:20:10
%S 1,0,0,0,42,0,0,0,840,0,0,0,10640,0,0,0,95802,0,0,0,652848,2097152,0,
%T 0,3504816,0,0,0,15266880,44040192,0,0,55350120,0,0,0,171361498,
%U 440401920,0,0,465944304,0,0,0,1145653488,2833252352,0,0,2610853840,0,0,0
%N Theta series of D*_21 lattice.
%D J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 120.
%H Andy Huchala, <a href="/A022074/b022074.txt">Table of n, a(n) for n = 0..1876</a>
%e G.f. = 1 + 42*q^4 + 840*q^8 + ...
%o (Magma)
%o L := Dual(Lattice("D", 21));
%o B := Basis(ThetaSeriesModularFormSpace(L), 60);
%o S := [1, 0, 0, 0, 42, 0, 0, 0, 840, 0, 0];
%o Coefficients(&+[B[i] * S[i] : i in [1..11]]); // _Andy Huchala_, Jul 14 2021
%K nonn
%O 0,5
%A _N. J. A. Sloane_
%E More terms from _Andy Huchala_, Jul 14 2021
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