%I #9 Jun 03 2022 11:17:08
%S 2,3,6,13,28,66,148,349,828,2005,4880,12043,29852,74645,187498,473448,
%T 1199630,3050554,7778234,19885465,50950796,130824763,336555890,
%U 867389312,2239220294,5789804688
%N Number of one-sided poly-[4.6.12]-tiles (holes allowed) with n cells (division into triangles is significant).
%D Branko Gruenbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 2.7, 6.2 and 9.4.
%Y Cf. A197462, A197464.
%K hard,nonn
%O 1,1
%A _Joseph Myers_, Oct 15 2011
%E a(20)-a(26) from _Aaron N. Siegel_, Jun 03 2022