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A153881
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1 followed by -1,-1,-1...
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17
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1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Dirichlet inverse of A002033.
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FORMULA
| a(n)=2*{C[2*(n-1),n-1] mod 2}-1, with n>=1 [From Paolo P. Lava (paoloplava(AT)gmail.com), Jan 22 2009]
G.f: x*(1-2*x)/(1-x). [From Mats Granvik (mats.granvik(AT)abo.fi), Mar 09 2009, rewritten R. J. Mathar (mathar(AT)strw.leidenuniv.nl, Mar 31 2010]
a(n)=(-1)^A000040(n). [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Sep 10 2009]
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CROSSREFS
| Sequence in context: A121238 A131554 * A160357 A057077 A070748 A154990
Adjacent sequences: A153878 A153879 A153880 * A153882 A153883 A153884
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KEYWORD
| sign,easy
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AUTHOR
| Mats Granvik (mats.granvik(AT)abo.fi), Jan 03 2009
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EXTENSIONS
| Edited by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Mar 18 2010
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