A231444 Number of (n+1) X (1+1) 0..3 arrays with no element unequal to a strict majority of its horizontal and antidiagonal neighbors, with values 0..3 introduced in row major order.

2, 6, 23, 102, 492, 2485, 12858, 67354, 355003, 1876862, 9937840, 52659593, 279141170, 1479959118, 7847200511, 41610135894, 220644482580, 1170015798397, 6204298839786, 32899919832226, 174460671091171, 925125214479854

Offset

1,1

Links

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

Formula

Empirical: a(n) = 11*a(n-1) - 41*a(n-2) + 65*a(n-3) - 43*a(n-4) + 9*a(n-5).

Empirical g.f.: x*(2 - 16*x + 39*x^2 - 35*x^3 + 9*x^4) / ((1 - x)*(1 - 3*x + x^2)*(1 - 7*x + 9*x^2)). - Colin Barker, Sep 28 2018

Example

Some solutions for n=7:
..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0
..1..1....1..1....1..1....1..1....1..1....1..1....0..1....1..1....1..1....0..1
..1..1....0..0....0..0....2..2....2..2....1..1....1..2....2..2....1..1....1..0
..0..0....2..2....0..0....3..3....3..3....2..2....2..3....1..1....1..2....0..0
..0..2....2..1....1..1....3..3....2..2....2..2....3..3....0..0....2..1....0..0
..2..2....1..1....1..1....0..0....3..3....2..1....0..0....3..3....1..0....0..0
..2..2....1..1....2..2....0..0....1..1....1..3....1..1....3..3....0..0....0..0
..2..2....0..0....3..3....0..0....3..3....3..3....3..3....0..0....3..3....1..1

Crossrefs

Column 1 of A231451.

Sequence in context: A263576 A370196 A370213 * A248900 A120346 A050389

Adjacent sequences: A231441 A231442 A231443 * A231445 A231446 A231447

Keyword

nonn

Author

R. H. Hardin, Nov 09 2013

Status

approved