16926797486domain: NAppears in sequencesTotal number of ordered k-tuples (k=0..n) of distinct elements from an n-element set: a(n) = Sum_{k=0..n} n!/k!.at n=13A000522Squarefree part of the total number of arrangements of a set with n elements.at n=13A222637a(n) = e*Gamma(2*n,1).at n=6A294039Nearest integer to e*n!.at n=13A370973