%I #14 May 02 2019 08:19:00
%S 0,0,7,9,85,67,139,70,23,12
%N Number of distinct (up to rotation and reflection) tic-tac-toe positions with n tokens which allow a winning strategy for X.
%C Including positions where X has already won (that is, 0 for even n, A048245(n) for odd n up to 7, and 12 for n = 9).
%H <a href="/index/Th#TTT">Index entries for sequences related to tic-tac-toe</a>
%e a(2) = 7:
%e x o . x . o x . . x . . . x . . x . . o .
%e . . . . . . . . o . . . o . . . . . . x .
%e . . . . . . . . . . . o . . . o . . . . .
%Y Cf. A008907, A317402, A048245.
%K fini,full,nonn
%O 0,3
%A _Álvar Ibeas_, Jul 27 2018