106175395755domain: NAppears in sequencesStirling numbers of second kind S(2n,n).at n=9A007820Stirling numbers of second kind S2(18,n).at n=8A011567Stirling numbers of second kind: 9th column of Stirling2 triangle A008277.at n=9A049447a(n) = Stirling2(n, ceiling(n/2)).at n=18A343278a(n) = Stirling2(n, floor(n/2)).at n=18A343279