338893domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes that remain prime through 4 iterations of function f(x) = 5x + 2.at n=26A023313Numbers 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 89.at n=4A031677Prime numbersat n=29109