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Search: id:A134314
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| -8, 8, -8, 16, -24, 24, -24, 32, -40, 40, -40, 48, -56, 56, -56, 64, -72, 72, -72, 80, -88, 88, -88, 96, -104, 104, -104, 112, -120, 120, -120, 128, -136, 136, -136, 144, -152, 152, -152, 160, -168, 168, -168, 176, -184, 184, -184, 192, -200, 200, -200, 208
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OFFSET
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0,1
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COMMENT
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Also fourth differences of (A057979 with (4n+3)-th terms negative = 1, n, -1, n+1). Also 8*(without 0, A004525 signed).
First differences: -1, -1, 2, 0, 1, -3, 4, -2, 3, -5, 6, -4, 5, -7, 8, -6, 7, -9 ...; second: 0, 3, -2, 1, -4, 7, -6, 5, -8, 11, -10, 9, -12 ... (cf. A092486); third: 3, -5, 3, -5, 11, -13, 11, -13, 19, -21, 19, -21, 27, -29, 27, -29, ... for which d(2n)+d(2n+1)=-A007395.
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FORMULA
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a(n)= -2*a(n-1)-2*a(n-2)-2*a(n-3)-a(n-4) = -8*(-1)^n*A004525(n+1). G.f.: -8(1+x+x^2)/((1+x^2)(1+x)^2). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 07 2009]
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MAPLE
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A134429 := proc(n) npr := floor(n/4) ; if (n mod 4 =0) or (n mod 4 = 2) then 8*npr+3 ; else -8*npr-5 ; fi; end: A134314 := proc(n) A134429(n+1)-A134429(n) ; end: seq(A134314(n), n=0..80) ; [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 07 2009]
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CROSSREFS
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Sequence in context: A166082 A145446 A023415 this_sequence A136050 A077106 A154707
Adjacent sequences: A134311 A134312 A134313 this_sequence A134315 A134316 A134317
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KEYWORD
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sign,easy
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AUTHOR
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Paul Curtz (bpcrtz(AT)free.fr), Jan 30 2008
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Mar 23 2008
More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 07 2009
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