84590domain: NAppears in sequencesNumbers with distinct digits appearing in partition of decimal expansion of e (A001113).at n=3A167836Number of regular graphs with half-edges on n labeled vertices.at n=7A322698a(n) = floor( Sum_{k=0..n-1} n^k / (k! * a(k)) ), for n > 0 with a(0) = 1.at n=20A357549