%I
%S 1,1,1,2,3,5,8,15,25,46,80,145,256,466,833,1513,2720,4925,8881,16063,
%T 28996,52373,94563,170620,307989,555214,1001774,1804594,3254229,
%U 5858448
%N Number of 2sided strip polyiamonds with n cells.
%H Ed Pegg, Jr., <a href="http://demonstrations.wolfram.com/PolyformExplorer/">Illustrations of polyforms</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Polyiamond.html">Polyiamond</a>
%K nonn,hard,more
%O 1,4
%A _Ed Pegg Jr_, May 13 2009
%E a(21)a(30) from _Joseph Myers_, Nov 27 2010
