3870793domain: NPropertiesPrimalityPrimeyesAppears in sequencesE.g.f. A(x) = exp(x+x^2+x^3+x^4+x^5+x^6+x^7).at n=9A193933Triangle read by rows: T(n,k) is the number of nilpotent subpermutations on an n-set, each of nilpotency index less than or equal to k.at n=52A261764Prime numbersat n=274671