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A123782
Number of ways to build a contiguous building with n LEGO blocks of size 1x4 on top of a fixed block of the same size.
0
23, 679, 27591, 1227556, 59212274, 2990304700, 156407426393
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
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Søren Eilers, Oct 29 2006
STATUS
approved