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