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Number of distinct prime divisors of 6^n + 1.
9

%I #15 Jan 07 2024 11:57:39

%S 1,1,1,2,1,3,3,3,2,3,3,2,2,4,3,5,3,3,6,3,3,5,4,3,4,4,4,5,5,4,9,2,3,6,

%T 3,10,5,4,3,9,5,4,7,2,3,7,5,2,7,5,6,8,4,5,10,7,6,7,3,2,6,3,2,9,3,8,11,

%U 5,5,6,7,4,5,6,4,10,5,5,10,6,6,8,4,5,8

%N Number of distinct prime divisors of 6^n + 1.

%H Max Alekseyev, <a href="/A366627/b366627.txt">Table of n, a(n) for n = 0..420</a>

%F a(n) = omega(6^n+1) = A001221(A062394(n)).

%t PrimeNu[6^Range[0,84] + 1] (* _Paul F. Marrero Romero_, Nov 11 2023 *)

%o (PARI) for(n = 0, 100, print1(omega(6^n + 1), ", "))

%Y Cf. A062394, A001221, A057938, A366620, A366628, A366629, A366630.

%Y Cf. A046799, A366580, A366605, A366615, A366636, A366655, A366664, A119704, A366686, A366712.

%K nonn

%O 0,4

%A _Sean A. Irvine_, Oct 14 2023