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Search: id:A156591
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| 2, -7, 6, -8, 4, -12, -4, -28, -36, -92, -164, -348, -676, -1372, -2724, -5468, -10916, -21852, -43684, -87388, -174756, -349532, -699044, -1398108, -2796196, -5592412, -11184804, -22369628, -44739236, -89478492, -178956964, -357913948, -715827876
(list; graph; listen)
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OFFSET
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0,1
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FORMULA
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a(n)+a(n+1) = -A000079(n-1), n>0.
a(n+1) = 4*(-1)^(n+1)- A154879(n).
G.f.: (1-3x)(2-3x)/((1+x)(1-2x)). a(n) = -2^n/6+20*(-1)^n/3, n>0. - R. J. Mathar (mathar(AT)strw.leidenunvi.nl), Feb 25 2009
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CROSSREFS
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Sequence in context: A047232 A103557 A158241 this_sequence A138283 A117968 A154200
Adjacent sequences: A156588 A156589 A156590 this_sequence A156592 A156593 A156594
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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), Feb 10 2009
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EXTENSIONS
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Edited by R. J. Mathar (mathar(AT)strw.leidenunvi.nl), Feb 25 2009
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