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A068211
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Largest prime factor of Euler Phi of n.
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10
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2, 2, 2, 2, 3, 2, 3, 2, 5, 2, 3, 3, 2, 2, 2, 3, 3, 2, 3, 5, 11, 2, 5, 3, 3, 3, 7, 2, 5, 2, 5, 2, 3, 3, 3, 3, 3, 2, 5, 3, 7, 5, 3, 11, 23, 2, 7, 5, 2, 3, 13, 3, 5, 3, 3, 7, 29, 2, 5, 5, 3, 2, 3, 5, 11, 2, 11, 3, 7, 3, 3, 3, 5, 3, 5, 3, 13, 2, 3, 5, 41, 3, 2, 7, 7, 5, 11, 3, 3, 11, 5, 23, 3, 2, 3, 7, 5, 5
(list; graph; refs; listen; history; internal format)
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OFFSET
| 3,1
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COMMENTS
| Smallest numbers m, such that largest prime-factor of Phi[m] is prime(n), the n-th prime is also a prime number and identical to n-th term of A035095: Min[x; A068211(x)=prime(n)]=A035095(n); e.g. Phi[a(7)]=Phi[103]=2.3.17 of which 17=p(7) is the largest prime-factor.
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LINKS
| T. D. Noe, Table of n, a(n) for n=3..1000
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FORMULA
| a(n)=A006530[A000010(n)]
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EXAMPLE
| n=46, Phi[46]=2.2.11, a(46)=11
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MATHEMATICA
| ffi[x_] := Flatten[FactorInteger[x]]; lf[x_] := Length[FactorInteger[x]]; ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}]; Table[Max[ba[EulerPhi[w]]], {w, 1, 256}]
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CROSSREFS
| Cf. A006530, A000010.
Cf. A035095, A035096.
Sequence in context: A078120 A057525 A139325 * A089050 A167439 A125173
Adjacent sequences: A068208 A068209 A068210 * A068212 A068213 A068214
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Feb 21 2002
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