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Search: id:A123771
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A123771 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1x3 which is symmetric after a rotation by 180 degrees. +0
1
1, 2, 12, 45, 264, 1128, 6991, 32202, 202856, 973242, 6204349 (list; graph; listen)
OFFSET

1,2

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: A028570 A009074 A066258 this_sequence A046991 A061990 A006742

Adjacent sequences: A123768 A123769 A123770 this_sequence A123772 A123773 A123774

KEYWORD

nonn

AUTHOR

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

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Last modified November 24 23:16 EST 2009. Contains 167481 sequences.


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