A198482 Number of 2n X 2 0..3 arrays with values 0..3 introduced in row major order and each element equal to an even number of horizontal and vertical neighbors.

5, 193, 10072, 528283, 27711478, 1453628917, 76251331828, 3999827976463, 209814352850962, 11005988987858473, 577328442763429648, 30284250801208664707, 1588585939401430092718, 83330616412779323165533

Offset

1,1

Comments

Column 1 of A198485.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 55*a(n-1) -135*a(n-2) +81*a(n-3) for n>4.

Empirical g.f.: x*(5 - 82*x + 132*x^2 - 27*x^3) / ((1 - x)*(1 - 54*x + 81*x^2)). - Colin Barker, May 14 2018

Example

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

Crossrefs

Cf. A198485.

Sequence in context: A100760 A240702 A240639 * A198523 A093154 A194572

Adjacent sequences: A198479 A198480 A198481 * A198483 A198484 A198485

Keyword

nonn

Author

R. H. Hardin, Oct 25 2011

Status

approved