This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A015229 #7 Jul 24 2021 01:08:13
%S A015229 1,0,432,1824,8100,21280,46030,95904,185276,265120,509976,735200,
%T A015229 1031016,1555200,2311880,2645984,4216860,5200000,6396192,8592480,
%U A015229 11519624,12022560,17652168,20269184,23363450,29522880,37500080,37249728,52312392,57561120,63690384
%N A015229 Theta series of lattice Kappa_11.
%D A015229 J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 161.
%H A015229 Andy Huchala, <a href="/A015229/b015229.txt">Table of n, a(n) for n = 0..1250</a>
%e A015229 G.f. = 1 + 432*q^4 + 1824*q^6 + ...
%o A015229 (Magma)
%o A015229 L := (Lattice("Kappa", 11));
%o A015229 B := Basis(ThetaSeriesModularFormSpace(L), 50);
%o A015229 S := [1, 0, 432, 1824, 8100, 21280, 46030, 95904, 185276, 265120, 509976, 735200, 1031016, 1555200, 2311880, 2645984, 4216860, 5200000, 6396192, 8592480, 11519624];
%o A015229 Coefficients(&+[B[i] * S[i] : i in [1..21]]); // _Andy Huchala_, Jul 23 2021
%K A015229 nonn
%O A015229 0,3
%A A015229 _N. J. A. Sloane_
%E A015229 More terms from _Andy Huchala_, Jul 23 2021