372555091domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = Sum_{k>=0} (Gamma(3*n+k-1)*Gamma((k+2)/3)/(Gamma(k)*Gamma(k+1)*Gamma(n-1/3+k/3)))/(3^(n-1)*exp(1)). Dobinski-type relation.at n=5A271049Prime numbersat n=19947679