A122271 a(n) is the smallest prime whose cube divides the numerator of the Bernoulli number B(A122270(n)).

5, 7, 5, 5, 7, 5, 5, 11, 7, 5, 5, 7, 5, 5, 13, 5, 7, 5, 7, 5, 5, 5, 7, 5, 7, 5, 11, 5, 5, 13, 7, 5, 7, 5, 17

Offset

1,1

Links

Table of n, a(n) for n=1..35.

The Bernoulli Number Page, Table of factors of the numerators of Bernoulli numbers Bn in the range n = 2..10000, 2018.

S. S. Wagstaff, Jr, Prime factors of the absolute values of Bernoulli numerators, 2018.

Example

a(1) = 5 because 5^3 divides numerator(B(A122270(1))) = numerator(B(250)), but 3^3 does not.

Crossrefs

Cf. A000367, A090997, A090987, A122270, A122272, A122273.

Sequence in context: A107437 A317083 A367549 * A011205 A167133 A144567

Adjacent sequences: A122268 A122269 A122270 * A122272 A122273 A122274

Keyword

nonn,more

Author

Alexander Adamchuk, Aug 28 2006

Extensions

Various sections edited by Petros Hadjicostas, May 12 2020

Status

approved