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A005567
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Number of walks on square lattice.
(Formerly M4723)
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1
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10, 70, 308, 1092, 3414, 9834, 26752, 69784, 176306, 434382, 1048812, 2490636, 5833006, 13500754, 30933368, 70255008, 158335434, 354419190, 788529700, 1744831060, 3841983110, 8422163130, 18387829488
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OFFSET
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0,1
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Simon Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
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LINKS
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Table of n, a(n) for n=0..22.
R. K. Guy, Catwalks, Sandsteps and Pascal Pyramids, J. Integer Seqs., Vol. 3 (2000), #00.1.6
_Simon Plouffe_, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
_Simon Plouffe_, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
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FORMULA
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a(n)=26 + 11*n + n^2 + (-16 + 24*n + 8*n^2)*2^n - fitted by John Layman )layman(AT)calvin.math.vt.edu)
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MAPLE
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A005567:=2*(5-10*z+4*z**2)/(2*z-1)**3/(z-1)**3; [Conjectured by Simon Plouffe in his 1992 dissertation.]
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CROSSREFS
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Sequence in context: A160662 A090084 A025221 * A174434 A073391 A002802
Adjacent sequences: A005564 A005565 A005566 * A005568 A005569 A005570
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane.
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STATUS
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approved
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