A204280 Number of (n+2) X 6 0..2 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..2 introduced in row major order.

1758, 193, 256, 244, 442, 982, 1914, 4922, 13138, 34498, 93778, 255730, 696018, 1900754, 5192146, 14180050, 38739154, 105835858, 289138770, 789939026, 2158150738, 5896157266, 16108595794, 44009496658, 120236140626, 328491234386

Offset

1,1

Comments

Column 4 of A204284.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -6*a(n-4) +4*a(n-6) for n>8.

Empirical g.f.: x*(1758 - 5081*x - 323*x^2 - 524*x^3 + 10258*x^4 + 814*x^5 - 6528*x^6 - 128*x^7) / ((1 - x)*(1 - 2*x - 2*x^2)*(1 - 2*x^3)). - Colin Barker, Jun 06 2018

Example

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

Crossrefs

Cf. A204284.

Sequence in context: A282480 A043436 A119406 * A252635 A213459 A186012

Adjacent sequences: A204277 A204278 A204279 * A204281 A204282 A204283

Keyword

nonn

Author

R. H. Hardin, Jan 13 2012

Status

approved