913139domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumbers of the concatenated form 9nn9.at n=13A102484Primes of the concatenated form 9nn9.at n=1A102503Numbers k such that k and k^2 use only the digits 1, 2, 3, 8 and 9.at n=22A136984Prime numbersat n=72248