OFFSET
0,2
COMMENTS
The ratio sequence of a(n)/A006955(n) begins: 1,1,1,1,1,1,1,1,1,5,1,5,1,7,1,1,7,1,1,35, ...
This divisibility by A006955 was confirmed by Peter Luschny in the SeqFan mailing list.
LINKS
Jean-François Alcover, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = (denominator of B(2n,x)) / (the squarefree kernel of 2n+1), where B(2n,x) is the 2n-th Bernoulli polynomial.
MATHEMATICA
sfk[n_] := Times @@ FactorInteger[n][[All, 1]];
a[n_] := (BernoulliB[2 n, x] // Together // Denominator)/sfk[2 n + 1];
Table[a[n], {n, 0, 60}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Jean-François Alcover and Paul Curtz, Mar 07 2019
STATUS
approved