login
A123766
Number of ways to build a contiguous building with n LEGO blocks of size 1 X 2 on top of a fixed block of the same size.
0
7, 58, 625, 7198, 90045, 1171813, 15798521, 218322975, 3078005599, 44090886228, 639937519413
OFFSET
1,1
COMMENTS
The base block is not counted among the n and must be the only block in the bottom layer of the building.
LINKS
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.
S. Eilers, The LEGO counting problem, Amer. Math. Monthly, 123 (May 2016), 415-426.
CROSSREFS
Sequence in context: A192940 A126130 A323254 * A377331 A362772 A005332
KEYWORD
nonn,hard,more
AUTHOR
Søren Eilers, Oct 29 2006
STATUS
approved