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 A124004 #30 Feb 10 2021 19:22:03 %S A124004 1,4,12,56,244,1396,8200,55092,390216,3005288,24571056,212258216, %T A124004 1939879668,18429618408,184041761768,1891831332208,20301171282452, %U A124004 222742563853912,2534535926617852,29335558770589276,349980362625040712,4228388321175157140 %N A124004 Number of possible Reversi games at the end of the n-th ply. %C A124004 Reversi is the older name for the game. Othello is a more recent trade name. %H A124004 Alain Brobecker, <a href="http://abrobecker.free.fr/text/othello.pdf">Othello and retrograde analysis (pdf)</a> %H A124004 Alain Brobecker, <a href="http://abrobecker.free.fr/tools/othello.zip">programs to generate sequences</a> %H A124004 Alain Brobecker, <a href="http://abrobecker.free.fr/tools/othello.c">othello.c</a> %H A124004 Dominic Hofer, <a href="https://github.com/PanicSheep/ReversiPerftCUDA/blob/master/docs/A124004.md">documentation and project to generate sequence</a> %Y A124004 Cf. A124005, A124006. %K A124004 fini,hard,nonn %O A124004 0,2 %A A124004 Alain Brobecker (abrobecker(AT)yahoo.com), Nov 01 2006, Dec 30 2006 %E A124004 a(15)-a(18) from _Paul Byrne_, Mar 08 2008 %E A124004 Edited by _Charles R Greathouse IV_, Oct 28 2009 %E A124004 a(19) from _Dominic Hofer_, Oct 21 2014 %E A124004 a(20) from _Dominic Hofer_, Jan 11 2021 %E A124004 a(21) from _Dominic Hofer_, Feb 11 2021