%I #29 Sep 11 2022 12:44:32

%S 2,5,4,8,3,8,4,10,7,8,4,13,3,9,7,13,4,12,4,14,7,9,5,18,5,8,12,13,5,14,

%T 5,16,9,8,7,18,5,9,8,18,5,15,4,15,12,9,4,22,8,11,10,13,5,18,6,19,10,9,

%U 6,24,6,11,11,20,9,17,6,14,10,18,4,26,7,10,11,13,9,17,4,24,17,12,9,22

%N Number of prime factors of 7^n - 1 (counted with multiplicity).

%H Max Alekseyev, <a href="/A057954/b057954.txt">Table of n, a(n) for n = 1..388</a> (first 378 terms from Amiram Eldar)

%H S. S. Wagstaff, Jr., <a href="https://homes.cerias.purdue.edu/~ssw/cun/index.html">The Cunningham Project</a>

%F Möbius transform of A085032. - _T. D. Noe_, Jun 19 2003

%F a(n) = A001222(A024075(n)). - _Amiram Eldar_, Feb 02 2020

%e 7^8-1 = 5764800 = 2^6 * 3 * 5^2 * 1201 and a(8) = bigomega(5764800) = 6+1+2+1 = 10. - _Bernard Schott_, Feb 02 2020

%t PrimeOmega[Table[7^n - 1, {n, 1, 30}]] (* _Amiram Eldar_, Feb 02 2020 *)

%o (Magma) f:=func<n|&+[p[2]: p in Factorization(n)]>; [f(7^n- 1):n in [1..85]]; // _Marius A. Burtea_, Feb 02 2020

%Y bigomega(b^n-1): A057951 (b=10), A057952 (b=9), A057953 (b=8), this sequence (b=7), A057955 (b=6), A057956 (b=5), A057957 (b=4), A057958 (b=3), A046051 (b=2).

%Y Cf. A001222, A024075, A059889, A074249, A085032.

%K nonn

%O 1,1

%A _Patrick De Geest_, Nov 15 2000