%I
%S 1,6,336,2521476,705277897416,7107572010747738816,
%T 2578606199622659276537193216,33678386561031835867238388699701784576,
%U 15835071665743319426540573726368249140484891508736
%N Number of 6colorings of an n X n grid, up to rotational symmetry.
%F a(n) = (m^(n^2) + 2 m^((n^2 + 3 (n mod 2))/4) + m^((n^2 + (n mod 2))/2))/4, with m = 6
%Y Cf. A047937A047945.
%K nonn
%O 0,2
%A _Rob Pratt_
