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Search: id:A123784
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| A123784 |
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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 so that the builing is flat, i.e. with all blocks in parallel position. |
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+0
1
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| 7, 55, 511, 5000, 51674, 547204, 5940045, 65472189, 731569499, 8258444996, 94045306573
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The base block is not counted among the n and must be the only block in the bottom layer of the building
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REFERENCES
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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
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LINKS
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S. Eilers, LEGO counts
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CROSSREFS
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Sequence in context: A096307 A124403 A005012 this_sequence A091695 A002882 A094905
Adjacent sequences: A123781 A123782 A123783 this_sequence A123785 A123786 A123787
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KEYWORD
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nonn,hard
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AUTHOR
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Soren Eilers (eilers(AT)math.ku.dk), Oct 29 2006
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