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 A006142 M4355 #14 Dec 27 2018 07:57:34 %S A006142 0,0,0,0,0,1,0,1,7,17,30,49,124,321,761,1721,3815 %N A006142 Number of certain self-avoiding walks with n steps on square lattice (see reference for precise definition). %D A006142 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A006142 W. A. Beyer and M. B. Wells, <a href="http://dx.doi.org/10.1016/0097-3165(72)90024-6">Lower bound for the connective constant of a self-avoiding walk on a square lattice</a>, J. Combin. Theory, A 13 (1972), 176-182, Table I. %Y A006142 Cf. A002976. %K A006142 nonn,walk %O A006142 4,9 %A A006142 _N. J. A. Sloane_