A223995 Number of nX4 0..2 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.

15, 155, 1144, 7927, 55333, 388598, 2743444, 19437479, 138010718, 981047716, 6977843175, 49645292212, 353262192994, 2513898151334, 17890175634324, 127318180862693, 906089796193803, 6448444001034017, 45892351529878911

Offset: 1

Author

R. H. Hardin Mar 30 2013

Keywords

• nonn

Comments

Column 4 of A223999

Examples

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

Links

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

Formula

Empirical: a(n) = 15*a(n-1) -69*a(n-2) +66*a(n-3) +226*a(n-4) -172*a(n-5) -1192*a(n-6) +2157*a(n-7) -1714*a(n-8) -2876*a(n-9) +4966*a(n-10) +12095*a(n-11) -17584*a(n-12) +28968*a(n-13) +156*a(n-14) -2874*a(n-15) -2964*a(n-16) +15876*a(n-17) +1008*a(n-18) for n>19