493447domain: NPropertiesPrimalityPrimeyesAppears in sequencesBase-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,3,2,0.at n=9A037709Numbers a(n) with property a(n) + a(n+4) = 2^(n+4) - 1 = A000225(n+4).at n=19A224520Prime numbersat n=41028