4444469domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) is the smallest prime greater than 4(10^n - 1)/9.at n=7A099658Prime numbers that are not repdigits with digits in nondecreasing order with the property that any nontrivial permutation of the digits gives a composite number.at n=42A364458Prime numbersat n=312298