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Number of 1-sided strip polyrhombs with n cells.
4

%I #7 Oct 02 2013 16:25:26

%S 1,2,4,10,20,48,106,252,578,1372,3208,7584,17850,42102,99276,233716,

%T 550960,1295146,3050226,7161346,16846668,39511876,92845830

%N Number of 1-sided strip polyrhombs with n cells.

%C Also counts 1-sided strip polyrects.

%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/Polyrhomb.html">Polyrhomb</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Polyrect.html">Polyrect</a>

%Y Strip polyominoes by group of symmetries relating shapes considered the same: A002013 (all symmetries), A182644 (translations only), A151514 (rotations and translations), A151527 (horizontal and vertical reflections, rotations of order 2 and translations), A151524 (reflections in either diagonal, rotations of order 2 and translations), A151523 (rotations of order 2 and translations), A151526 (reflections in a horizontal line and translations), A182646 (reflections in a NE-SW diagonal line and translations)

%K nonn,hard,more

%O 1,2

%A _Ed Pegg Jr_, May 13 2009

%E Edited and a(15)-a(23) by _Joseph Myers_, Nov 24 2010