%I #9 Jan 07 2022 11:09:59
%S 1,4,6,21,47,134,323,876,2224,5885,15146,39574,102250,265574,686208,
%T 1775646,4583718,11835037,30515520,78652647
%N Number of 1-sided strip polytans 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/Polytan.html">Polytan</a>
%Y Cf. A006074, A151521.
%K nonn,hard,more
%O 1,2
%A _Ed Pegg Jr_, May 13 2009
%E a(6)-a(20) from _John Mason_, Jan 07 2022