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 A006536 M1710 #20 Jun 17 2022 16:19:31 %S A006536 2,6,38,684,50224,13946352,14061131152,50947324188128, %T A006536 666754350781269760,31763991166456912086656, %U A006536 5550343429517595744902558208,3581353054755185129132443153728000 %N A006536 Switching classes of digraphs. %D A006536 R. C. Read, personal communication. %D A006536 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A006536 R. C. Read, <a href="/A000684/a000684_1.pdf">Letter to N. J. A. Sloane, Oct. 29, 1976</a> %Y A006536 Cf. A002854, A049313. %K A006536 nonn,nice %O A006536 1,1 %A A006536 _N. J. A. Sloane_ %E A006536 More terms from _Vladeta Jovovic_, Jul 22 2000