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

1,2

Comments

Column 4 of A202979

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)

Example

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

Crossrefs

Sequence in context: A225160 A219974 A266051 * A051816 A015566 A238810

Adjacent sequences: A202972 A202973 A202974 * A202976 A202977 A202978

Keyword

nonn

Author

R. H. Hardin Dec 26 2011

Status

approved