A004085 - OEIS

A004085

Sum of digits of Euler totient function of n.

1, 1, 2, 2, 4, 2, 6, 4, 6, 4, 1, 4, 3, 6, 8, 8, 7, 6, 9, 8, 3, 1, 4, 8, 2, 3, 9, 3, 10, 8, 3, 7, 2, 7, 6, 3, 9, 9, 6, 7, 4, 3, 6, 2, 6, 4, 10, 7, 6, 2, 5, 6, 7, 9, 4, 6, 9, 10, 13, 7, 6, 3, 9, 5, 12, 2, 12, 5, 8, 6, 7, 6, 9, 9, 4, 9, 6, 6, 15, 5, 9, 4, 10, 6, 10

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OFFSET

1,3

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A007953(A000010(n)). - Michel Marcus, Dec 18 2016

MAPLE

f:= n -> convert(convert(numtheory:-phi(n), base, 10), `+`):

map(f, [$1..100]); # Robert Israel, Dec 05 2017

MATHEMATICA

Total/@(IntegerDigits/@EulerPhi[Range[70]]) (* Harvey P. Dale, Jul 31 2013 *)