References to 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, 1, 8, 135, 3386, 120469, 5767884, 357666403, 27886211102, 2670067220337

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