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A236753
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Number of simple (non-intersecting) directed paths on the grid graph P_n X P_n.
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2
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1, 28, 653, 28512, 3060417, 873239772, 687430009069, 1532025110398168, 9829526954625359697, 183563561823425961932572, 10056737067604248527218979485, 1626248896102138091401810358337184
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OFFSET
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1,2
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COMMENTS
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This is the number of directed paths on P_n X P_n of any length and also includes one zero length path per vertex. - Andrew Howroyd, May 27 2017
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LINKS
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FORMULA
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EXAMPLE
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For n=2 there are 4 zero length paths (one for each vertex), 8 paths with 1 one edge, 8 paths with 2 edges and 8 paths with 3 edges, so a(2)=28. - Andrew Howroyd, May 27 2017
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CROSSREFS
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Cf. A236690 (includes diagonal edges).
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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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