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Search: id:A070862
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| A070862 |
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Number of path covers of an n X n grid. |
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+0
2
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| 1, 15, 1803, 2015052, 20582691507, 1928747601908977, 1657680158728377785062, 13067714049552363383420892169, 944866406096482421853329114821597865
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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A path cover is set of disjoint paths such that each node of the graph belongs to exactly one of these. A Hamiltonian path is a special path cover consisting of a single path. Paths of length zero (i.e. single nodes) are permitted.
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EXAMPLE
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a(1) = 1 as there is only the trivial cover by a single path of length 0
a(2) = 15 = 1 (all length 0) + 4 (2x0, 1x1) + 2 (2x1) + 4 (1x2, 1x0) + 4 (1x3)
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CROSSREFS
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Sequence in context: A119784 A122184 A069450 this_sequence A077730 A110103 A126681
Adjacent sequences: A070859 A070860 A070861 this_sequence A070863 A070864 A070865
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KEYWORD
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nonn
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AUTHOR
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Andre Poenitz (poenitz(AT)htwm.de), Nov 26 2003
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