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 A007274 M4222 #14 Feb 02 2022 16:06:29 %S A007274 1,6,36,216,1260,7206,40650,227256,1262832,6983730,38470224,211220814, %T A007274 1156489782,6317095284,34435495872,187380150468,1018035642054 %N A007274 Walks on hexagonal lattice using each point at most twice. %C A007274 The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice. %C A007274 Guttmann et al. has incorrect a(10) = 38470220, a(11) = 211220800, a(12) = 1156490000. - _Sean A. Irvine_, Dec 02 2017 %D A007274 A. J. Guttmann, C. Byrnes and N. E. Frankel, A generalized self-avoiding walk, J. Phys. A 17 (1984), L457-L461. %D A007274 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A007274 G. Nebe and N. J. A. Sloane, <a href="http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/A2.html">Home page for hexagonal (or triangular) lattice A2</a> %Y A007274 Cf. A001334, A007275. %K A007274 nonn,walk %O A007274 0,2 %A A007274 _Simon Plouffe_ %E A007274 Title improved, a(10)-a(12) corrected, and a(15)-a(16) added by _Sean A. Irvine_, Dec 02 2017