A084217 Number of k's 1<=k<=n dividing the numerator of 2n-th Bernoulli number.

1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 1, 2, 2, 1, 3, 2, 1, 2, 2, 1, 2, 1, 2, 2, 4, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 2, 2, 1, 3, 1, 2, 3, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 1, 1, 4, 2, 2, 2, 2, 3, 2, 1, 2, 2, 3, 2, 4, 1, 2, 2, 1, 2, 2, 1, 4, 2, 2, 3, 2, 1, 4, 2, 2, 2, 5, 1, 2, 3, 2, 1

Offset

1,4

Links

Table of n, a(n) for n=1..99.

Prog

(PARI) a(n)=sum(k=1, n, if(numerator(bernfrac(2*n))%k, 0, 1))

Crossrefs

Sequence in context: A227945 A003647 A353352 * A245548 A025903 A175327

Adjacent sequences: A084214 A084215 A084216 * A084218 A084219 A084220

Keyword

nonn

Author

Benoit Cloitre, Jun 21 2003

Status

approved