23169481domain: NPropertiesPrimalityPrimeyesAppears in sequencesTriangular array read by rows. T(n,k) is the number of binary relations R on [n] such that the unique idempotent in {R^i:i>=1} contains exactly k non-arcless strongly connected components, n>=0, 0<=k<=n.at n=16A370464Prime numbersat n=1458274