68546domain: NAppears in sequencesExpansion of Product_{k=1..12} theta_3(q^k), where theta_3() is the Jacobi theta function.at n=45A320246Number of permutations f of {1,...,n} such that 3^k + 3^(f(k)) - 1 is prime for every k = 1,...,n.at n=17A321766a(n) = Sum_k k*A333275(n,k).at n=17A333277