%I #9 Mar 30 2012 17:28:41
%S 0,0,0,0,0,5,39,394,2784,19164,118762,579460,3110267,15264387,
%T 75007623,369928203,1817475619,8913862144,43914857957,216555328193,
%U 1070588132492
%N Number of polyhexes with n cells that do not tile the plane.
%D M. Gardner, Tiling with Polyominoes, Polyiamonds and Polyhexes. Chap. 14 in Time Travel and Other Mathematical Bewilderments. New York: W. H. Freeman, pp. 175-187, 1988.
%H Joseph Myers, <a href="http://www.polyomino.org.uk/mathematics/polyform-tiling/">Polyhex tiling</a>
%Y Cf. A000228, A070766, A038144, A070768, A054360.
%K hard,nonn
%O 1,6
%A _Joseph Myers_, May 05 2002
%E More terms from _Joseph Myers_, Nov 06 2003
%E a(20) and a(21) from _Joseph Myers_, Nov 21 2010