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 A014747 #16 Oct 21 2018 13:40:30 %S A014747 1,0,760,0,77560,524288,2508000,10485760,34729720,99614720,259114704, %T A014747 608174080,1327461600,2739404800,5341699520,9921626112,17701924600, %U A014747 30592204800,51294999960,83277905920,131880275664 %N A014747 Theta series of lattice D20+. %D A014747 J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 120. %H A014747 Seiichi Manyama, <a href="/A014747/b014747.txt">Table of n, a(n) for n = 0..10000</a> (terms 0..2500 from G. C. Greubel) %F A014747 G.f.: (theta2(q)^20 + theta3(q)^20 + theta4(q)^20)/2. %t A014747 terms = 21; s = 1/2 (EllipticTheta[2, 0, q]^20 + EllipticTheta[3, 0, q]^20 + EllipticTheta[4, 0, q]^20) + O[q]^terms; CoefficientList[s, q] (* _Jean-François Alcover_, Jul 07 2017 *) %Y A014747 Cf. A022051. %K A014747 nonn %O A014747 0,3 %A A014747 _N. J. A. Sloane_