A205468 Number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having the same number of equal edges, and new values 0..2 introduced in row major order.

14, 48, 175, 677, 2709, 11143, 46709, 198483, 851317, 3674723, 15929949, 69254347, 301652741, 1315582371, 5742416845, 25079258843, 109571246421, 478835560339, 2092898539805, 9148671997707, 39994487184037, 174849254952131

Offset

1,1

Comments

Column 1 of A205475.

Links

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

Formula

Empirical: a(n) = 9*a(n-1) - 21*a(n-2) - 11*a(n-3) + 66*a(n-4) - 6*a(n-5) - 36*a(n-6).

Empirical g.f.: x*(14 - 78*x + 37*x^2 + 264*x^3 - 105*x^4 - 180*x^5) / ((1 - x)*(1 - 3*x)*(1 - 2*x - 2*x^2)*(1 - 3*x - 6*x^2)). - Colin Barker, Mar 04 2018

Example

Some solutions for n=4:
..0..0....0..0....0..0....0..1....0..0....0..0....0..0....0..0....0..1....0..0
..0..1....0..1....0..1....1..1....1..0....0..0....1..2....1..2....0..2....1..2
..0..1....0..0....1..1....2..1....1..1....0..0....1..0....0..2....1..2....0..2
..1..1....1..0....0..0....1..1....2..2....0..0....2..2....0..1....0..0....0..1
..1..2....1..0....1..0....1..2....2..1....0..0....0..1....0..2....2..1....2..2

Crossrefs

Cf. A205475.

Sequence in context: A205753 A332606 A232826 * A195966 A337421 A345724

Adjacent sequences: A205465 A205466 A205467 * A205469 A205470 A205471

Keyword

nonn

Author

R. H. Hardin, Jan 27 2012

Status

approved