66733domain: 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 39.at n=4A031627Primes which contain the fax number of the beast (667).at n=27A321001Primes in A284798.at n=12A372770Prime numbersat n=6651