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Search: id:A123776
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| A123776 |
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Number of ways to build a contiguous building with n LEGO blocks of size 1x3 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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| 5, 28, 185, 1287, 9456, 71167, 549076, 4300975, 34154107, 273998400, 2217436152, 18074303774, 148232462372
(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: A020081 A095676 A006157 this_sequence A070779 A024065 A003467
Adjacent sequences: A123773 A123774 A123775 this_sequence A123777 A123778 A123779
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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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