44720640domain: NAppears in sequencesa(n) = n! (1/C(n,0) + 1/C(n,1) + ... + 1/C(n,[ n/2 ])).at n=11A024419a(n) = n!*Sum_{m=0..floor(n/2)} binomial(n,2*m)^(-1).at n=11A358791