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A069988 (-1)^(n+1)/6*sum(k=1,2n+1,C(2n+1,k)*B(k)*3^k) where C(n,k) are the binomial coefficients, B(k) the Bernoulli numbers. 0
0, 1, 8, 135, 3386, 120469, 5767884, 357666403, 27886211102, 2670067220337, 308003491726640, 42129829536116671, 6742323657098884098, 1248097176923675241805, 264614795104954119229076 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..15.

PROG

(PARI) for(n=1, 25, print1(-(-1)^n*sum(i=1, 2*n+1, binomial(2*n+1, i)*bernfrac(i)*3^i)/6, ", "))

CROSSREFS

Sequence in context: A003375 A007032 A215553 * A229237 A291699 A292914

Adjacent sequences:  A069985 A069986 A069987 * A069989 A069990 A069991

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, May 01 2002

STATUS

approved

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Last modified November 21 17:44 EST 2017. Contains 295004 sequences.