3114313domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = 7*b_7(n) + 6, where b_7 lists the indices of zeros of the sequence u(n) = abs(u(n-1) - gcd(u(n-1), 7n-1)), u(1) = 1.at n=6A186259Prime numbersat n=224449