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A069992
(-1)^(n+1)/3*sum(k=1,2n,C(2n+1,k)*B(k)*6^k) where C(n,k) are the binomial coefficients, B(k) the Bernoulli numbers.
0
3, 57, 2123, 138609, 13883283, 1974243241, 378027128283, 93761532169953, 29240923237509923, 11199084302796542745, 5167442341466021937003, 2827285169201754895553617, 1809878752362221218378054323
OFFSET
1,1
PROG
(PARI) for(n=1, 25, print1(-(-1)^n*sum(i=1, 2*n, binomial(2*n+1, i)*bernfrac(i)*6^i)/3, ", "))
CROSSREFS
Sequence in context: A254570 A308404 A009723 * A012196 A012090 A210674
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, May 01 2002
STATUS
approved