A250669 Number of (n+1)X(1+1) 0..3 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.

104, 520, 2512, 11736, 53032, 233300, 1005121, 4260728, 17835379, 73930174, 304111433, 1243471948, 5060483311, 20518170938, 82950532885, 334582615528, 1347111707003, 5416107760342, 21751360774177, 87278063198468

Offset: 1

Author

R. H. Hardin, Nov 26 2014

Keywords

• nonn

Comments

Column 1 of A250676

Examples

			Some solutions for n=4
..2..1....2..0....0..2....2..0....0..0....0..0....1..1....1..0....2..1....0..1
..0..3....1..2....1..1....1..1....0..2....0..1....0..2....0..1....0..3....0..3
..2..1....1..2....1..1....0..2....1..1....1..3....1..3....0..1....0..3....0..3
..3..0....2..1....2..2....0..2....2..2....2..2....2..2....0..3....3..0....2..1
..0..3....2..2....1..3....1..1....3..1....2..3....2..2....2..1....0..3....1..3
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 16*a(n-1) -106*a(n-2) +376*a(n-3) -769*a(n-4) +904*a(n-5) -564*a(n-6) +144*a(n-7) for n>11