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A123832
Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 3 X 3.
0
1, 7, 227, 9130, 408081, 19274998, 946866202, 47865420384, 2473743947058
OFFSET
1,2
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.CO/0504039
CROSSREFS
Sequence in context: A303533 A372967 A142606 * A093167 A157693 A221029
KEYWORD
nonn,hard
AUTHOR
Søren Eilers, Oct 29 2006
STATUS
approved