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A130472
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A permutation of the integers: a(n)=((-1)^n)*floor((n+1)/2).
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5
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0, -1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7, -8, 8, -9, 9, -10, 10, -11, 11, -12, 12, -13, 13, -14, 14, -15, 15, -16, 16, -17, 17, -18, 18, -19, 19, -20, 20, -21, 21, -22, 22, -23, 23, -24, 24, -25, 25, -26, 26, -27, 27, -28, 28, -29, 29, -30, 30, -31, 31, -32, 32
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OFFSET
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0,4
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COMMENTS
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Pisano period lengths: 1, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40,... - R. J. Mathar, Aug 10 2012
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LINKS
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Table of n, a(n) for n=0..64.
Index to sequences with linear recurrences with constant coefficients, signature (-1,1,1).
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FORMULA
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a(n)=-A001057(n); a(2n)=n, a(2n+1)=-n-1; a(n)=sum{k*(-1)^k: k=0,1,...,n}; a(n)=-a(n-1)+a(n-2)+a(n-3).
G.f. x / ( (x-1)*(1+x)^2 ). - R. J. Mathar, Feb 20 2011
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CROSSREFS
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Cf. A001057.
Sequence in context: A168050 A065033 A001057 * A076938 A004526 A140106
Adjacent sequences: A130469 A130470 A130471 * A130473 A130474 A130475
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KEYWORD
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sign
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AUTHOR
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Clark Kimberling, May 28 2007
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STATUS
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approved
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