%I #20 Oct 08 2017 05:15:47
%S 1,1,7,11,76,135,942,1812,12537,25246,174019,362458,2485725
%N Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 2 which is symmetric after a rotation by 180 degrees.
%H M. Abrahamsen and S. Eilers, <a href="http://dx.doi.org/10.1080/10586458.2011.564539">On the asymptotic enumeration of LEGO structures</a>, Exper Math. 20 (2) (2011) 145-152.
%H B. Durhuus and S. Eilers, <a href="http://arxiv.org/abs/math/0504039">On the entropy of LEGO</a>, arXiv:math/0504039 [math.CO], 2005.
%H S. Eilers, <a href="http://www.math.ku.dk/~eilers/lego.html">A LEGO Counting problem</a>, 2005.
%H S. Eilers, <a href="http://www.jstor.org/stable/10.4169/amer.math.monthly.123.5.415">The LEGO counting problem</a>, Amer. Math. Monthly, 123 (May 2016), 415-426.
%H <a href="/wiki/Index_to_OEIS:_Section_Lc#LEGO">Index entry for sequences related to LEGO blocks</a>
%K nonn,more
%O 1,3
%A _Søren Eilers_, Oct 29 2006