2290792933domain: NAppears in sequencesRencontres numbers: number of permutations of [n] with exactly one fixed point.at n=12A000240a(n) = ceiling(n!/e) with e = A001113 = exp(1).at n=13A174318a(n) = A000166(floor(n/2)) if n is even otherwise A000240(floor((n + 1)/2)).at n=25A371998