203341domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 31.at n=26A031619Primes p such that p-2, p^2-2 and p^3-2 are all prime.at n=22A270972Prime numbersat n=18252