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Search: id:A087429
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| A087429 |
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a(n) = if gpf(n) < gpf(n+1) then 1 else 0, where gpf=A006530 (greatest prime-factor). |
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+0
3
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| 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Equivalently, a(n) = 1 iff A061395(n+1) > A061395(n), otherwise a(n) = 0. - Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Jan 03 2008
a(n) = A057427(1+A057427(A070221(n)));
for primes p: a(p-1)=1 and a(p)=0;
a(A070089(n)) = 1, a(A070087(n)) = 0, a(A087430(n)) = 0.
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MATHEMATICA
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Join[{1}, Table[If[PrimePi[FactorInteger[n + 1][[ -1, 1]]] > PrimePi[FactorInteger[n][[ -1, 1]]], 1, 0], {n, 2, 90}]] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jan 06 2008
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CROSSREFS
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Cf. A061395.
Sequence in context: A071040 A078387 A105470 this_sequence A093075 A104120 A108336
Adjacent sequences: A087426 A087427 A087428 this_sequence A087430 A087431 A087432
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Sep 02 2003
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Jul 01 2008, at the suggestion of R. J. Mathar
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