22667domain: NAppears in sequencesa(n) = smallest number > a(n-1) such that a(1)*a(2)*...*a(n) + 1 and a(1)*a(2)*...*a(n) - 1 are primes.at n=43A051956a(n) = 81*n^2 - 44*n + 6.at n=17A156676