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

Author

Alexander Adamchuk, Aug 28 2006

Keywords

• nonn
• more

Examples

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

Links

• 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.

Crossrefs

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

Extensions

Various sections edited by Petros Hadjicostas, May 12 2020