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 A005965 M1651 #16 Oct 12 2017 04:19:17 %S A005965 1,2,6,20,91,506 %N A005965 Erroneous version of A000421. %D A005965 A. T. Balaban, Enumeration of Cyclic Graphs, pp. 63-105 of A. T. Balaban, ed., Chemical Applications of Graph Theory, Ac. Press, 1976; see p. 92. %D A005965 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %K A005965 dead %O A005965 1,2 %A A005965 _N. J. A. Sloane_