29552671domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes of the form 2*n^4-1.at n=18A182784a(n) = Sum_{1 <= x_1, x_2, x_3, x_4 <= n} gcd(x_1, x_2, x_3, x_4, n)^5.at n=30A372937Prime numbersat n=1831770