124529domain: 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 28.at n=20A031616Primes p such that (12*p - 1, 12*p + 1) and (18*p - 1, 18*p + 1) are twin primes.at n=15A138660Prime numbersat n=11695