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A087073
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Mobius transform of A051664, the number of nonzero terms in the n-th cyclotomic polynomial.
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2
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2, 0, 1, 0, 3, 0, 5, 0, 0, 0, 9, 0, 11, 0, 1, 0, 15, 0, 17, 0, 1, 0, 21, 0, 0, 0, 0, 0, 27, 0, 29, 0, 3, 0, 7, 0, 35, 0, 3, 0, 39, 0, 41, 0, 0, 0, 45, 0, 0, 0, 5, 0, 51, 0, 3, 0, 5, 0, 57, 0, 59, 0, 0, 0, 15, 0, 65, 0, 7, 0, 69, 0, 71, 0, 0, 0, 15, 0, 77, 0, 0, 0, 81, 0, 21, 0, 9, 0, 87, 0, 5, 0, 9, 0, 9
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Note that a(n) = 0 for even n and a(n) = n-2 for prime n. It appears that the following are true: a(1) is the only positive even term, all odd numbers eventually appear in the sequence, a(n) = 0 if n is squareful and a(n) > 0 if n is squarefree. Assuming the truth of the last statement, we can show that if distinct odd primes p and q divide n, then A051664(n) > p + q - 2.
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
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FORMULA
| a(n) = Sum{d|n} mu(n/d) A051664(d)
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CROSSREFS
| Cf. A051664.
Sequence in context: A175790 A177825 A124305 * A106844 A125989 A125924
Adjacent sequences: A087070 A087071 A087072 * A087074 A087075 A087076
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KEYWORD
| nonn
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AUTHOR
| T. D. Noe (noe(AT)sspectra.com), Aug 08 2003
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EXTENSIONS
| Definition corrected: "inverse moebius transform" to "moebius transform" by Wouter Meeussen (wouter.meeussen(AT)pandora.be), Jan 17 2009
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