A250657 Number of (3+1)X(n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

39, 70, 109, 156, 211, 274, 345, 424, 511, 606, 709, 820, 939, 1066, 1201, 1344, 1495, 1654, 1821, 1996, 2179, 2370, 2569, 2776, 2991, 3214, 3445, 3684, 3931, 4186, 4449, 4720, 4999, 5286, 5581, 5884, 6195, 6514, 6841, 7176, 7519, 7870, 8229, 8596, 8971

Offset: 1

Author

R. H. Hardin, Nov 26 2014

Keywords

• nonn

Comments

Row 3 of A250656

Examples

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

Links

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

Formula

Empirical: a(n) = 4*n^2 + 19*n + 16