A208265 Number of n X 4 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or left-upward diagonal neighbors.

8, 89, 1033, 11929, 137845, 1592731, 18403423, 212644499, 2457026181, 28390000737, 328035635669, 3790326714043, 43795780208895, 506043544208099, 5847140236199813, 67561476345437377, 780647102957445445

Offset

1,1

Comments

Column 4 of A208269.

Links

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

Formula

Empirical: a(n) = 10*a(n-1) + 20*a(n-2) - 21*a(n-3) - 30*a(n-4) + 8*a(n-5).

Empirical g.f.: x*(8 + 9*x - 17*x^2 - 13*x^3 + 4*x^4) / (1 - 10*x - 20*x^2 + 21*x^3 + 30*x^4 - 8*x^5). - Colin Barker, Jun 29 2018

Example

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

Crossrefs

Cf. A208269.

Sequence in context: A319842 A072352 A099100 * A184756 A295244 A379546

Adjacent sequences: A208262 A208263 A208264 * A208266 A208267 A208268

Keyword

nonn

Author

R. H. Hardin, Feb 24 2012

Status

approved