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 A121790 #4 Mar 30 2012 16:50:30 %S A121790 0,6,81,2420,158487,22668546,7067228903,4796951277784, %T A121790 7083189530689311,22740544515287098346,158673902903632923216807, %U A121790 2405521769596577026409223804,79215226453280152797069512845071 %N A121790 "Hamiltonian cow patches" on the square lattice (see Jensen web site for further information). %H A121790 I. Jensen, <a href="/A121790/b121790.txt">Table of n, a(n) for n = 1..18</a> [from the Jensen link below] %H A121790 I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/saw/SAW_ser.html">Series Expansions for Self-Avoiding Walks</a> %K A121790 nonn %O A121790 1,2 %A A121790 _N. J. A. Sloane_, Aug 30 2006