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%I #14 Feb 09 2020 08:39:34
%S 0,0,0,0,0,1,1,1,1,1,2,3,2,2,3,3,3,2,1,2,2,1,5,3,3,3,5,3,4,5,3,5,2,3,
%T 6,5,2,2,3,4,5,4,5,4,4,4,4,6,5,6,5,7,5,5,3,6,4,2,5,2,3,4,9,4,6,7,4,5,
%U 4,8,8,4,2,7,7,7,7,8,5,8,6,5,8,9,6,5,3,8
%N Number of distinct prime factors of the numerator of the 2n-th Bernoulli number.
%H Amiram Eldar, <a href="/A079294/b079294.txt">Table of n, a(n) for n = 0..103</a>
%H S. S. Wagstaff, Jr., <a href="http://www.cerias.purdue.edu/homes/ssw/bernoulli/bnum">Factors of Bernoulli numbers</a>
%F a(n) = A001221(abs(A000367(n))). - _Amiram Eldar_, Feb 09 2020
%t Table[PrimeNu[Numerator[BernoulliB[2n]]], {n, 0, 30}] (* _Amiram Eldar_, Feb 09 2020 *)
%o (PARI) a(n)=omega(numerator(bernfrac(2*n)))
%Y Cf. A001221, A000367, A046886.
%K nonn
%O 0,11
%A _Benoit Cloitre_, Feb 09 2003
%E More terms from _T. D. Noe_, Feb 13 2004
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