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A079294 Number of distinct prime factors of the numerator of the 2n-th Bernoulli number. 5
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, 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, 4, 8, 8, 4, 2, 7, 7, 7, 7, 8, 5, 8, 6, 5, 8, 9, 6, 5, 3, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,11

LINKS

Amiram Eldar, Table of n, a(n) for n = 0..103

S. S. Wagstaff, Jr., Factors of Bernoulli numbers

FORMULA

a(n) = A001221(abs(A000367(n))). - Amiram Eldar, Feb 09 2020

MATHEMATICA

Table[PrimeNu[Numerator[BernoulliB[2n]]], {n, 0, 30}] (* Amiram Eldar, Feb 09 2020 *)

PROG

(PARI) a(n)=omega(numerator(bernfrac(2*n)))

CROSSREFS

Cf. A001221, A000367, A046886.

Sequence in context: A309806 A256170 A051686 * A242789 A076733 A079643

Adjacent sequences:  A079291 A079292 A079293 * A079295 A079296 A079297

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Feb 09 2003

EXTENSIONS

More terms from T. D. Noe, Feb 13 2004

STATUS

approved

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Last modified September 26 01:25 EDT 2020. Contains 337346 sequences. (Running on oeis4.)