A197626 - OEIS

%I #5 Mar 30 2012 17:28:44

%S 1,1,4,11,35,110,392,1372,4998,18251,67792,253043,952534,3602846,

%T 13699554,52298066

%N Number of free poly-IH61 tiles (holes allowed) with n cells.

%C Equivalently, one-sided poly-IH73-tiles.

%D Branko Gruenbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 6.2 and 9.4.

%Y Cf. A056779.

%K hard,nonn

%O 1,3

%A _Joseph Myers_, Oct 16 2011