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A070777
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a(1) = 1; a(n) = Euler Phi of largest prime-factor of n.
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10
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1, 1, 2, 1, 4, 2, 6, 1, 2, 4, 10, 2, 12, 6, 4, 1, 16, 2, 18, 4, 6, 10, 22, 2, 4, 12, 2, 6, 28, 4, 30, 1, 10, 16, 6, 2, 36, 18, 12, 4, 40, 6, 42, 10, 4, 22, 46, 2, 6, 4, 16, 12, 52, 2, 10, 6, 18, 28, 58, 4, 60, 30, 6, 1, 12, 10, 66, 16, 22, 6, 70, 2, 72, 36, 4, 18, 10, 12, 78, 4, 2, 40, 82, 6
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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FORMULA
| a(n)=A000010[A006530(n)]
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EXAMPLE
| n=102=2.3.17: a(102)=phi[17]=16.
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MAPLE
| with(numtheory): A070777 := n -> `if`(n=1, 1, phi(max(op(factorset(n))))): [From Peter Luschny (peter(AT)luschny.de), Oct 23 2010]
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MATHEMATICA
| a[n_] := EulerPhi[Last[FactorInteger[n]][[1]]]; Table[a[n], {n, 1, 200}] [From J.M. Grau Ribas (grau(AT)telecable.es), Feb 21 2010]
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CROSSREFS
| Cf. A000010, A006530, A068211, A070812.
Sequence in context: A057923 A147763 A098371 * A173614 A023900 A173557
Adjacent sequences: A070774 A070775 A070776 * A070778 A070779 A070780
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KEYWORD
| easy,nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), May 07 2002
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