4556099domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumber of nonempty subsets of {1,2,...,n} with no gap of length greater than 4 (a set S has a gap of length d if a and b are in S but no x with a < x < b is in S, where b-a=d).at n=22A119407Prime numbersat n=319581