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Search: id:A112389
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| A112389 |
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Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 2 X 4. |
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+0
2
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| 1, 24, 1560, 119580, 10166403, 915103765, 85747377755, 8274075616387
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(6) is often quoted as 102981500, but this is incorrect.
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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 entropy of LEGO, arXiv:math.CO/0504039
Anthony Lane, The Joy of Bricks, New Yorker, Apr 27-May 04, 1998, pp. 96-103.
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LINKS
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S. Eilers, LEGO counts
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CROSSREFS
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Cf. A112390.
Sequence in context: A035174 A063885 A019284 this_sequence A054777 A084224 A166788
Adjacent sequences: A112386 A112387 A112388 this_sequence A112390 A112391 A112392
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KEYWORD
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nonn,hard
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Dec 06 2005
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EXTENSIONS
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Thanks to Gerald McGarvey, Schneelocke [Christian Schroeder] and Jud McCranie who contributed to this entry.
a(8) from Soren Eilers (eilers(AT)math.ku.dk), Oct 29 2006
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