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Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 2.
64

%I #33 Jan 14 2017 13:18:22

%S 1,4,37,375,4493,56848,753536,10283622,143607345,2041497919,

%T 29446248496,429858432108

%N Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 2.

%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 B. Durhuus and S. Eilers, <a href="http://link.springer.com/article/10.1007/s12190-013-0730-9">On the entropy of LEGO</a>, J. Appl. Math. Comput. 45 (1-2) (2014), 433-448.

%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>

%Y Cf. A007576, A082679, A112389, A112390.

%K nonn,hard,more

%O 1,2

%A _Søren Eilers_, Oct 29 2006