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A123835
Number of ways to build a contiguous building with n LEGO blocks of size 3 X 3 on top of a fixed block of the same size.
0
25, 757, 29925, 1281402, 59340183, 2862828262, 142920335981, 7311973715989
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.CO/0504039
CROSSREFS
Sequence in context: A217996 A246906 A286439 * A012835 A277584 A223228
KEYWORD
nonn,hard
AUTHOR
Søren Eilers, Oct 29 2006
STATUS
approved