622620domain: NAppears in sequencesNumber of double rises at an even level in all nondecreasing Dyck paths of semilength n. A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.at n=13A121532Numbers k such that k^7 - 1 and k^7 + 1 are semiprimes.at n=29A279272