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 A193454 Sum of odd divisors of phi(n). 3

%I #18 Jan 08 2017 13:02:16

%S 1,1,1,1,1,1,4,1,4,1,6,1,4,4,1,1,1,4,13,1,4,6,12,1,6,4,13,4,8,1,24,1,

%T 6,1,4,4,13,13,4,1,6,4,32,6,4,12,24,1,32,6,1,4,14,13,6,4,13,8,30,1,24,

%U 24,13,1,4,6,48,1,12,4,48,4,13,13,6,13,24,4

%N Sum of odd divisors of phi(n).

%C Phi(n): A000010 is the Euler totient function. This sequence equals A193254(n) for n < 63.

%H Indranil Ghosh, <a href="/A193454/b193454.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A000593(A000010(n)). - _Michel Marcus_, Jan 14 2014

%e a(63) = 13 because phi(63) = 36, and the sum of the 3 odd divisors {1, 3, 9} is 13.

%t Table[Total[Select[Divisors[EulerPhi[n]], OddQ[ # ]&]], {n, 58}]

%o (PARI) a(n) = sumdiv(eulerphi(n), d, (d%2)*d); \\ _Michel Marcus_, Jan 14 2014

%Y Cf. A000010, A193254.

%K nonn

%O 1,7

%A _Michel Lagneau_, Jul 26 2011

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Last modified August 7 21:19 EDT 2024. Contains 375017 sequences. (Running on oeis4.)