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Number of distinct prime factors of totient of (n-th prime)!.
2

%I #12 Sep 28 2017 06:04:58

%S 0,1,1,2,3,3,4,4,5,6,6,7,8,8,9,9,10,10,11,11,11,12,13,14,15,15,15,16,

%T 16,16,18,18,19,19,21,21,21,22,23,23,24,24,24,24,25,25,27,29,30,30,30,

%U 30,30,30,31,32,32,32,33,34,34,34,36,36,36,37,38,39,40,40,40,41,42,42

%N Number of distinct prime factors of totient of (n-th prime)!.

%H G. C. Greubel, <a href="/A055930/b055930.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A001221(A055929(n)).

%t Table[PrimeNu[EulerPhi[Prime[n]!]], {n, 1, 50}] (* _G. C. Greubel_, May 13 2017 *)

%o (PARI) for(n=1,50, print1(omega(eulerphi(prime(n)!)) , ", ")) \\ _G. C. Greubel_, May 13 2017

%Y Cf. A001221, A039716.

%K nonn

%O 1,4

%A _Labos Elemer_, Jul 17 2000