147331domain: NPropertiesPrimalityPrimeyesAppears in sequencesSmallest prime factor of G+n, where G is any sufficiently large power tower of 3, e.g., Graham's number.at n=16A152177a(n) = numerator of Sum_{i=1..n} 1/A031216(i).at n=9A375525Prime numbersat n=13620