A266076 Number of n X 3 integer arrays with each element equal to the number of horizontal and vertical neighbors differing from itself by exactly one.

2, 4, 4, 6, 5, 12, 10, 16, 21, 31, 42, 66, 89, 132, 191, 280, 407, 601, 873, 1281, 1875, 2748, 4024, 5902, 8642, 12667, 18562, 27204, 39866, 58431, 85627, 125494, 183918, 269545, 395034, 578955, 848492, 1243527, 1822475, 2670967, 3914489, 5736967

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + a(n-3) + a(n-6) - a(n-7) - a(n-9).

Empirical g.f.: x*(2 + 2*x - 5*x^4 + 3*x^5 - 10*x^6 - x^7 - 7*x^8) / ((1 - x)*(1 + x)*(1 - x + x^2)*(1 + x + x^2)*(1 - x - x^3)). - Colin Barker, Jan 09 2019

Example

All solutions for n=4:
..0..0..0....1..2..1....0..0..0....2..1..1....2..3..2....1..1..2
..2..3..2....1..2..1....0..0..0....1..1..2....3..4..3....2..1..1
..3..4..3....1..2..1....0..0..0....1..1..2....2..3..2....2..1..1
..2..3..2....1..2..1....0..0..0....2..1..1....0..0..0....1..1..2

Crossrefs

Column 3 of A266081.

Sequence in context: A365264 A152782 A307119 * A074325 A058249 A340226

Adjacent sequences: A266073 A266074 A266075 * A266077 A266078 A266079

Keyword

nonn

Author

R. H. Hardin, Dec 20 2015

Status

approved