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A080647 Sum of prime factors of phi(n). 1
2, 2, 2, 2, 5, 2, 5, 2, 7, 2, 5, 5, 2, 2, 2, 5, 5, 2, 5, 7, 13, 2, 7, 5, 5, 5, 9, 2, 10, 2, 7, 2, 5, 5, 5, 5, 5, 2, 7, 5, 12, 7, 5, 13, 25, 2, 12, 7, 2, 5, 15, 5, 7, 5, 5, 9, 31, 2, 10, 10, 5, 2, 5, 7, 16, 2, 13, 5, 14, 5, 5, 5, 7, 5, 10, 5, 18, 2, 5, 7, 43, 5, 2, 12, 9, 7, 13, 5, 5, 13, 10, 25, 5, 2, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

LINKS

Indranil Ghosh, Table of n, a(n) for n = 3..10000

FORMULA

a(n) = A008472(A000010(n)). - Indranil Ghosh, Jan 18 2017

EXAMPLE

For n = 11, phi(11) = 10 which has prime factors 2 and 5. So, 2+5 = 7 and a(11) = 7. - Indranil Ghosh, Jan 18 2017

MATHEMATICA

Table[Apply[Plus, Transpose[FactorInteger[EulerPhi[n]]][[1]]], {n, 3, 100}]

CROSSREFS

Cf. A000010, A008472.

Sequence in context: A221491 A224254 A107604 * A324516 A181058 A301452

Adjacent sequences:  A080644 A080645 A080646 * A080648 A080649 A080650

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Feb 28 2003

STATUS

approved

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Last modified December 9 19:51 EST 2019. Contains 329879 sequences. (Running on oeis4.)