213973domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes that remain prime through 4 iterations of the function f(x) = 3x + 4.at n=11A023308Numbers 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 40.at n=11A031628Prime numbersat n=19125