A204281 Number of (n+2) X 7 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.

5263, 539, 334, 442, 736, 996, 2168, 5368, 13024, 34864, 94528, 255360, 696608, 1902112, 5191264, 14181088, 38741728, 105833952, 289140704, 789944032, 2158146784, 5896160992, 16108605664, 44009488608, 120236147936, 328491253984

Offset

1,1

Comments

Column 5 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*(5263 - 15250*x - 1283*x^2 - 560*x^3 + 30988*x^4 + 2022*x^5 - 19868*x^6 - 640*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..1..2..0..2....0..1..2..0..0..2..2....0..0..0..0..0..0..0
..0..1..0..1..2..0..2....0..1..2..0..0..2..2....1..1..1..1..1..1..1
..0..1..0..1..2..0..2....0..1..2..0..0..2..2....2..2..2..2..2..2..2
..0..1..0..1..2..0..2....0..1..2..0..0..2..2....0..0..0..0..0..0..0
..0..1..0..1..2..0..2....0..1..2..0..0..2..2....2..2..2..2..2..2..2
..0..1..0..1..2..0..2....0..1..2..0..0..2..2....1..1..1..1..1..1..1

Crossrefs

Cf. A204284.

Sequence in context: A206379 A234229 A143936 * A251901 A274361 A223494

Adjacent sequences: A204278 A204279 A204280 * A204282 A204283 A204284

Keyword

nonn

Author

R. H. Hardin, Jan 13 2012

Status

approved