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A080736
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Multiplicative function defined by a(1)=1, a(2)=0, a(2^r) = phi(2^r) (r>1), a(p^r) = phi(p^r) (p odd prime, r>=1), where phi is Euler's function A000010.
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1
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1, 0, 2, 2, 4, 0, 6, 4, 6, 0, 10, 4, 12, 0, 8, 8, 16, 0, 18, 8, 12, 0, 22, 8, 20, 0, 18, 12, 28, 0, 30, 16, 20, 0, 24, 12, 36, 0, 24, 16, 40, 0, 42, 20, 24, 0, 46, 16, 42, 0, 32, 24, 52, 0, 40, 24, 36, 0, 58, 16, 60, 0, 36, 32, 48, 0, 66, 32, 44, 0, 70, 24, 72, 0, 40, 36, 60, 0, 78, 32
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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PROG
| (PARI) {for(n=1, 81, f=factor(n); print1(if(n==1, 1, if(f[1, 1]==2&&f[1, 2]==1, 0, prod(j=1, matsize(f)[1], eulerphi(f[j, 1]^f[j, 2])))), ", "))}
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CROSSREFS
| Cf. A080737.
Sequence in context: A127786 A030207 A061006 * A144412 A113750 A004565
Adjacent sequences: A080733 A080734 A080735 * A080737 A080738 A080739
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KEYWORD
| nonn,easy,mult
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Mar 08 2003
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EXTENSIONS
| More terms and PARI code from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Mar 10 2003
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