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Search: id:A063866
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| A063866 |
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Number of solutions to +- 1 +- 2 +- 3 +- ... +- n = 1. |
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+0
9
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| 0, 1, 1, 0, 0, 3, 5, 0, 0, 23, 40, 0, 0, 221, 397, 0, 0, 2410, 4441, 0, 0, 28460, 53222, 0, 0, 353743, 668273, 0, 0, 4559828, 8679280, 0, 0, 60400688, 115633260, 0, 0, 817175698, 1571588177, 0, 0, 11243980807, 21704569869, 0, 0, 156860869714
(list; graph; listen)
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OFFSET
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0,6
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REFERENCES
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Suggested by J. H. Conway (conway(AT)math.princeton.edu), Aug 27, 2001.
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LINKS
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T. D. Noe, Table of n, a(n) for n=0..100
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MATHEMATICA
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f[n_, s_] := f[n, s]=Which[n==0, If[s==0, 1, 0], Abs[s]>(n*(n+1))/2, 0, True, f[ n-1, s-n]+f[n-1, s+n]]; a[n_] := f[n, 1]
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CROSSREFS
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Cf. A025591, A063865, A063867.
Sequence in context: A059107 A025115 A113037 this_sequence A059106 A087676 A058813
Adjacent sequences: A063863 A063864 A063865 this_sequence A063867 A063868 A063869
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KEYWORD
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nonn,easy,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Aug 27 2001
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EXTENSIONS
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More terms from Dean Hickerson and Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 28, 2001
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