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 A061894 #13 May 13 2021 01:34:10 %S A061894 0,2,2,4,6,13,35,171,1934,97151,52942129,1435382350480, %T A061894 21191828466255176653 %N A061894 Lionel-Levine-sequence generated by (2,0). %e A061894 a(3) = 4: (2,0),(2,2),(1,1,2,2),(1,1,2,2,3,4) %Y A061894 Cf. A011784, A061892, A061895. %K A061894 nonn,easy %O A061894 0,2 %A A061894 _Frank Ellermann_, May 13 2001 %E A061894 a(10) from _Naohiro Nomoto_, May 10 2002 %E A061894 a(11) and a(12) from _Michael Anthony Keyes_, May 12 2021