A202975 Number of nX4 0..1 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.

1, 7, 58, 385, 2582, 17740, 122468, 846908, 5858575, 40519184, 280214415, 1937863565, 13401760093, 92683431379, 640976755990, 4432841883249, 30656469034888, 212012773252576, 1466229429328620, 10140090725898534

Offset: 1

Author

R. H. Hardin Dec 26 2011

Keywords

• nonn

Comments

Column 4 of A202979

Examples

			Some solutions for n=5
..1..1..0..0....1..1..1..0....1..1..0..0....1..1..1..1....0..1..1..0
..1..1..1..1....1..0..1..1....1..1..1..1....1..0..1..1....1..1..1..1
..0..0..1..1....1..0..0..1....1..1..1..1....1..0..1..0....1..0..1..1
..0..1..1..1....1..0..1..1....1..1..1..1....1..1..1..1....1..1..0..1
..0..1..1..0....1..1..1..0....0..1..1..0....0..1..1..1....0..1..1..1
		

Links

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

Formula

Empirical: a(n) = 10*a(n-1) -31*a(n-2) +82*a(n-3) -131*a(n-4) +226*a(n-5) -319*a(n-6) +206*a(n-7) -574*a(n-8) +483*a(n-9) -432*a(n-10) +517*a(n-11) +132*a(n-12) +746*a(n-13) -145*a(n-14) -228*a(n-15) -6*a(n-16) +41*a(n-17) +3*a(n-18) -3*a(n-19)