A123762 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 2.

1, 4, 37, 375, 4493, 56848, 753536, 10283622, 143607345, 2041497919, 29446248496, 429858432108

Offset

1,2

Links

Table of n, a(n) for n=1..12.

M. Abrahamsen and S. Eilers, On the asymptotic enumeration of LEGO structures, Exper Math. 20 (2) (2011) 145-152.

B. Durhuus and S. Eilers, On the entropy of LEGO, arXiv:math/0504039 [math.CO], 2005.

B. Durhuus and S. Eilers, On the entropy of LEGO, J. Appl. Math. Comput. 45 (1-2) (2014), 433-448.

S. Eilers, A LEGO Counting problem, 2005.

S. Eilers, The LEGO counting problem, Amer. Math. Monthly, 123 (May 2016), 415-426.

Index entry for sequences related to LEGO blocks

Crossrefs

Cf. A007576, A082679, A112389, A112390.

Sequence in context: A197966 A199690 A133462 * A371753 A326014 A220914

Adjacent sequences: A123759 A123760 A123761 * A123763 A123764 A123765

Keyword

nonn,hard,more

Author

Søren Eilers, Oct 29 2006

Status

approved