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Search: id:A006481
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| A006481 |
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Euler characteristics of polytopes.
(Formerly M0533)
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+0
2
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| 1, 2, 3, 4, 5, 11, 21, 36, 57, 127, 253, 463, 793, 1717, 3433, 6436, 11441, 24311, 48621, 92379, 167961, 352717, 705433, 1352079, 2496145, 5200301, 10400601, 20058301, 37442161
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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H. Hadwiger and P. Mani, On polyhedra with extremal Euler characteristic, J. Combin. Theory, A 17 (1974), 345-349.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
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Numbers suggest that for n not divisible by 4, a(n) = C(n, [n/2]) + 1 and C(n, [(n-1)/2]) + 1 otherwise (see A051920 and A037952+1). - R. Stephan, Jun 07 2005
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CROSSREFS
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Very like A051920.
Sequence in context: A073528 A116067 A063685 this_sequence A118597 A083160 A123823
Adjacent sequences: A006478 A006479 A006480 this_sequence A006482 A006483 A006484
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KEYWORD
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nonn,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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