10699776685domain: NAppears in sequencesa(n) = n! * Sum_{k=1..n-1} 1/k!.at n=13A038156Multiply by 1, add 1, multiply by 2, add 2, etc.at n=26A082459a(n) = Sum_{r < n, gcd(r,n)=1} n!/r!.at n=12A110377Expansion of e.g.f. (exp(x)-x)*x/(1-x).at n=13A296964