OFFSET
0,5
COMMENTS
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..10000
FORMULA
a(n) = - (2n+1)*Bernoulli(2n) mod 2n+1.
EXAMPLE
-(2*1+1)*Bernoulli(2*1) = -3*(1/6) = -1/2 == -2 == 1 mod 3, so a(1) = 1.
MAPLE
a:= n-> -(2*n+1)*bernoulli(2*n) mod (2*n+1):
seq(a(n), n=0..100); # Alois P. Heinz, Aug 13 2013
MATHEMATICA
a[ n_ ] := Mod[ Numerator[ -(2 n + 1)* BernoulliB[ 2 n]] * PowerMod[ Denominator[(2 n + 1)* BernoulliB[ 2 n]], -1, 2 n + 1], 2 n + 1]
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Sondow, Aug 13 2013
STATUS
approved