%I #11 Nov 29 2017 03:38:18
%S 1,13,25,352,1006,15510,46928,744211,2479362
%N Number of ways to build a contiguous building with n LEGO blocks of size 2 X 3 on top of a fixed block of the same size so that the building is symmetric after a rotation by 180 degrees.
%C The base block is not counted among the n and must be the only block in the bottom layer of the building.
%H <a href="/wiki/Index_to_OEIS:_Section_Lc#LEGO">Index entry for sequences related to LEGO blocks</a>
%Y Cf. A112389, A123762 - A123827, A123829 - A123849.
%K nonn,more
%O 1,2
%A _Søren Eilers_, Oct 29 2006