9612108domain: NAppears in sequencesa(n) = T(4*n,n), where T = Catalan triangle (A008315).at n=8A0260059th column of Catalan triangle A009766.at n=17A124087Number of North-East lattice paths from (0,0) to (n,n) that cross the diagonal y = x horizontally exactly four times.at n=8A268447