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Search: id:A153881
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| A153881 |
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1 followed by -1,-1,-1... |
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+0
16
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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; listen)
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OFFSET
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1,1
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COMMENT
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Dirichlet inverse of A002033.
(-1)^nth prime [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Sep 24 2009]
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FORMULA
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a(n)=2*{C[2*(n-1),n-1] mod 2}-1, with n>=1 [From Paolo P. Lava (ppl(AT)spl.at), Jan 22 2009]
G.f: -x/(1-x^-1)*(1-2*x)*(x^-1). [From Mats Granvik (mats.granvik(AT)abo.fi), Mar 09 2009]
a(n)=(-1)^A000040(n). [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Sep 10 2009]
a(n)=(-1)^(phi(A008578(n))-A008578(n))=(-1)^(A002033(A008578(n))-d(A008578(n)). [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Oct 28 2009]
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CROSSREFS
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Cf. A000005, A000010, A000040, A002033, A008578. [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Oct 28 2009]
Sequence in context: A127252 A121238 A131554 this_sequence A160357 A070748 A154990
Adjacent sequences: A153878 A153879 A153880 this_sequence A153882 A153883 A153884
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KEYWORD
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sign,new
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AUTHOR
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Mats Granvik (mats.granvik(AT)abo.fi), Jan 03 2009
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