268435470domain: NAppears in sequencesa(n) = 2^n + ceiling(n/2).at n=28A134522a(n) = 4^n + n.at n=14A158879Number of (n+1) X (3+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nonincreasing x(i,j)-x(i-1,j) in the j direction.at n=26A250737