297670187844domain: NAppears in sequencesSuper ballot numbers: 6(2n)!/(n!(n+2)!).at n=24A007054a(n) = 6*(2n-4)!/((n-2)!n!), if n>2. a(0) = 1, a(1) = a(2) = 2.at n=26A091712a(n) = 3/(n + 1) * Catalan(2*n).at n=12A387248