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Search: id:A051436
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| A051436 |
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Undirected walks of length n+1 on tetrahedron, visiting n+2 vertices, with n "corners", as in A001998, but allowing only rigid motions in 3-space (|G| = 12). Walks are not self-avoiding. |
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+0
2
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| 1, 2, 5, 12, 39, 111, 350, 1044, 3201, 9627, 29150, 87672, 264069, 793431, 2384450, 7159164, 21494001, 64507827, 193589270, 580878432, 1742897949, 5229157551, 15688522250
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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n=2m: (3^n+3^m)/2 -2^(n-1)+2^(m-1); n=2m+1: (3^n+3^m)/2 - 2^(n-1) +1
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EXAMPLE
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For n=2 there are three walks that stay in one face and two that visit two faces.
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CROSSREFS
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Cf. A001998, A001444.
Sequence in context: A036782 A050237 A050258 this_sequence A054581 A140440 A005664
Adjacent sequences: A051433 A051434 A051435 this_sequence A051437 A051438 A051439
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KEYWORD
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nonn,nice,easy
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AUTHOR
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Colin Mallows colinm(AT)research.avayalabs.com
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EXTENSIONS
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Corrected by T. D. Noe (noe(AT)sspectra.com), Nov 09 2006
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