332473domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes with 20 as smallest positive primitive root.at n=3A061332Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in an em 1,1 1,2 2,2 2,3 3,3 in any orientation.at n=10A146151Prime numbersat n=28603