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 A014452 #16 Jul 08 2025 05:39:08 %S A014452 1,2,6,12,2,0,18,12,6,14,12,12,12,0,12,36,2,12,42,12,0,0,24,24,18,14, %T A014452 12,48,12,0,48,12,6,36,12,24,14,0,24,48,12,12,72,36,12,0,24,24,12,14, %U A014452 30,72,0,0,54,24,12,48,36,12,36,0,36,84,2,24,48,36,12,0,24,24,42,24,36,60,12 %N A014452 Theta series of quadratic form with Gram matrix [ 1, 0, 0; 0, 2, 1; 0, 1, 2 ]. %C A014452 This is the hexagonal P lattice (the classical holotype) of dimension 3. %H A014452 John Cannon, <a href="/A014452/b014452.txt">Table of n, a(n) for n = 0..10000</a> %H A014452 G. Nebe and N. J. A. Sloane, <a href="http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/hexagonalP.html">Home page for this lattice</a> %e A014452 1 + 2*q + 6*q^2 + 12*q^3 + 2*q^4 + 18*q^6 + 12*q^7 + 6*q^8 + 14*q^9 + 12*q^10 + ... %K A014452 nonn %O A014452 0,2 %A A014452 _N. J. A. Sloane_