280284364800domain: NAppears in sequencesInteger values of k!!/S(k), where S(k) is the sum of all odd numbers less than or equal to k, if k is odd, or the sum of all even numbers less than or equal to k, if k is even.at n=9A130318Denominators of numbers with g.f. exp(1-(1-x)^(1/2)).at n=12A143968