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 A005880 M1827 #26 Dec 01 2017 03:02:02
%S A005880 2,8,12,16,26,24,28,48,36,40,64,48,62,80,60,64,96,96,76,112,84,88,156,
%T A005880 96,114,144,108,144,160,120,124,208,168,136,192,144,148,248,192,160,
%U A005880 242,168,216,240
%N A005880 Theta series of D_4 lattice with respect to edge.
%D A005880 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A005880 G. C. Greubel, <a href="/A005880/b005880.txt">Table of n, a(n) for n = 0..5000</a>
%H A005880 <a href="/index/Da#D4">Index entries for sequences related to D_4 lattice</a>
%t A005880 Table[2 DivisorSigma[1, 2 n + 1], {n, 0, 43}] (* _Jean-François Alcover_, Jul 06 2017 *)
%o A005880 (PARI) for(n=0, 30, print1(2*sigma(2*n+1), ", ")) \\ _G. C. Greubel_, Nov 30 2017
%Y A005880 Equals 2 * A008438.
%K A005880 nonn
%O A005880 0,1
%A A005880 _N. J. A. Sloane_