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A123808 Number of ways to build a contiguous building with n LEGO blocks of size 1x7 on top of a fixed block of the same size so that the builing is flat, i.e. with all blocks in parallel position. 0
13, 190, 3289, 59970, 1154985, 22797643, 461266481, 9477047041 (list; graph; refs; listen; history; internal format)
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

REFERENCES

M. Abrahamsen and S. Eilers, Efficient counting of LEGO buildings, in preparation

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

LINKS

S. Eilers, LEGO counts

CROSSREFS

Sequence in context: A057801 A094736 A055613 * A103731 A000563 A159196

Adjacent sequences:  A123805 A123806 A123807 * A123809 A123810 A123811

KEYWORD

nonn,hard

AUTHOR

Soren Eilers (eilers(AT)math.ku.dk), Oct 29 2006

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Last modified February 15 17:42 EST 2012. Contains 205829 sequences.