357666403domain: NPropertiesPrimalityPrimeyesAppears in sequences(-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.at n=7A069988Prime numbersat n=19192893