A231257 Number of (n+1) X (2+1) 0..2 arrays with no element unequal to a strict majority of its horizontal and antidiagonal neighbors, with values 0..2 introduced in row major order.

3, 15, 89, 547, 3381, 20911, 129329, 799835, 4946509, 30591143, 189187465, 1170008467, 7235785189, 44748896799, 276744502881, 1711495152971, 10584548667901, 65458946997783, 404823472069561, 2503585087356803

Offset

1,1

Comments

Column 2 of A231263.

Links

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

Formula

Empirical: a(n) = 10*a(n-1) -29*a(n-2) +36*a(n-3) -16*a(n-4).

Empirical g.f.: x*(1 - 2*x)*(3 - 9*x + 8*x^2) / ((1 - x)*(1 - 9*x + 20*x^2 - 16*x^3)). - Colin Barker, Feb 16 2018

Example

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

Crossrefs

Sequence in context: A365128 A127785 A287511 * A074541 A368974 A074550

Adjacent sequences: A231254 A231255 A231256 * A231258 A231259 A231260

Keyword

nonn

Author

R. H. Hardin, Nov 06 2013

Status

approved