%I #42 Sep 07 2023 23:34:18
%S 1,2,16,164,1866,22518,282184,3630256,47614214,633835642,8537220172
%N Number of distinct connected planar figures that can be formed from n 1 X 2 rectangles (or dominoes).
%C "Connected" means "connected by edges".
%C Rotations and reflections are considered different (cf. A056786).
%C Internal arrangement of dominoes is significant (cf. A056785). - _Aaron N. Siegel_, May 22 2022
%H Manfred Scheucher, <a href="/A216598/a216598.sage.txt">Sage Script</a>.
%H N. J. A. Sloane, <a href="/A056786/a056786.jpg">Illustration of initial terms of A056786, A216598, A216583, A216595, A216492, A216581</a>.
%H N. J. A. Sloane, <a href="/A056786/a056786.pdf">Illustration of third term of A056786, A216598, A216583, A216595, A216492, A216581</a> (a better drawing for the third term).
%H M. Vicher, <a href="http://www.vicher.cz/puzzle/polyforms.htm">Polyforms</a>.
%H <a href="/index/Do#domino">Index entries for sequences related to dominoes</a>
%Y Cf. A056786, A216598, A216583, A216595, A216492, A216581.
%K nonn,more,nice,hard
%O 0,2
%A _N. J. A. Sloane_, Sep 09 2012
%E a(4) found via equivalence class decomposition over bounding boxes by the Forest Grove Community School Math Club - _Markus J. Q. Roberts_, Apr 03 2013
%E a(5)-a(9) from _Manfred Scheucher_, Jun 06 2015
%E a(10) from _Aaron N. Siegel_, May 22 2022