30651domain: NAppears in sequencesa(n) = a(n-1)^2 + 2*a(n-2).at n=4A113785Conjectured smallest Sierpiński numbers of the second kind S, base b=2,3,4,5,..., where S*b^n+1 is composite for all n>=1 and gcd(S+1, b-1) = 1.at n=22A123159Floor(sqrt(7*2^n)).at n=27A221943Numbers k such that 7*10^k + 57 is prime.at n=32A270974