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%I #11 Dec 05 2014 02:44:27
%S 1,1,1,3,4,12,23,66,133,316,514,1987,2398,6073,12628,29918,26211,
%T 108778,95348,375045,498168,780434,843319,4981628,3691212,7357764,
%U 13169722,33461765,22372303,117437124
%N Number of polyiamonds with n cells that tile the plane isohedrally.
%C A tiling is isohedral if the symmetries of the tiling act transitively on the tiles; a shape is anisohedral if it tiles the plane, but not isohedrally.
%D Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4.
%H Joseph Myers, <a href="http://www.polyomino.org.uk/mathematics/polyform-tiling/">Polyiamond tiling</a>
%Y Cf. A071332, A075216, A075217, A075218, A075219, A075220, A075221, A075222, A075224, A075205, A075214.
%K hard,nonn
%O 1,4
%A _Joseph Myers_, Sep 08 2002
%E More terms from _Joseph Myers_, Nov 11 2003
%E a(29) and a(30) from _Joseph Myers_, Nov 21 2010