OFFSET
1,1
COMMENTS
For each m in the current sequence, the smallest prime p such that p^4 divides the numerator of the Bernoulli number B(m) is listed in A122273.
Note that the numerator of B(6250) is divisible by 5^5.
The current sequence is a subsequence of A122270, which are the numbers m such that the numerator of the Bernoulli number B(m) is divisible by a cube.
Sequence A122270 itself is a subsequence of A090997, which are the numbers m such that the numerator of the Bernoulli number B(m) is divisible by a square. [Edited by Petros Hadjicostas, May 12 2020]
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.
EXAMPLE
a(1) = 1250 because 5^4 divides numerator(B(1250)).
a(3) = 4802 because 7^4 divides numerator(B(4802)).
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Alexander Adamchuk, Aug 28 2006
STATUS
approved