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%I #19 Apr 29 2022 15:59:57
%S 2,4,3,6,4,7,3,8,5,7,3,10,3,7,7,11,4,11,5,11,6,8,4,13,8,7,9,10,5,14,4,
%T 14,6,8,9,16,5,10,6,15,4,16,4,12,12,8,3,17,4,13,8,12,5,19,10,13,7,9,4,
%U 21,5,9,11,18,8,15,7,14,9,16,4,22,5,10,16,14,7,14,5,20,11,10,5,22,9,10
%N Number of prime factors of 5^n - 1 (counted with multiplicity).
%H Max Alekseyev, <a href="/A057956/b057956.txt">Table of n, a(n) for n = 1..502</a> (first 448 terms from Amiram Eldar)
%H S. S. Wagstaff, Jr., <a href="http://www.cerias.purdue.edu/homes/ssw/cun/index.html">The Cunningham Project</a>
%F Mobius transform of A085030. - _T. D. Noe_, Jun 19 2003
%F a(n) = A001222(A024049(n)). - _Amiram Eldar_, Feb 01 2020
%t PrimeOmega[5^Range[90]-1] (* _Harvey P. Dale_, Dec 16 2017 *)
%Y bigomega(b^n-1): A057951 (b=10), A057952 (b=9), A057953 (b=8), A057954 (b=7), A057955 (b=6), this sequence (b=5), A057957 (b=4), A057958 (b=3), A046051 (b=2).
%Y Cf. A001222, A024049, A074479, A085030.
%K nonn
%O 1,1
%A _Patrick De Geest_, Nov 15 2000