A186583 Number of (n+3) X 6 0..2 arrays with every 4 X 4 subblock commuting with each horizontal and vertical neighbor 4 X 4 subblock.

38608, 1991, 5879, 39757, 115699, 149305, 156259, 160945, 165739, 171145, 185131, 230017, 470139, 778697, 1118323, 1529121, 2339979, 3298521, 4347171, 5627937, 8189067, 11662681, 15995763, 21614673, 31416027, 44959433, 62319075, 84811905

Offset

1,1

Comments

Column 3 of A186589.

Links

R. H. Hardin, Table of n, a(n) for n = 1..150

Formula

Empirical: a(n) = 2*a(n-1) - a(n-2) + 2*a(n-4) - 4*a(n-5) + 2*a(n-6) + 2*a(n-8) - 2*a(n-9) for n>13

Empirical g.f.: x*(38608 - 75225*x + 40505*x^2 + 29990*x^3 - 35152*x^4 + 108114*x^5 - 107662*x^6 - 62248*x^7 - 161236*x^8 + 158518*x^9 + 54108*x^10 - 32320*x^11 + 43136*x^12) / ((1 - x)*(1 - x - 2*x^4 + 2*x^5 - 2*x^8)). - Colin Barker, Apr 18 2018

Example

Some solutions for 5 X 6:
..0..0..0..0..0..0....1..1..1..1..1..1....0..0..0..2..0..2....1..0..0..0..0..0
..0..0..0..0..0..0....0..2..0..2..0..2....0..0..0..0..0..0....0..0..0..0..0..0
..0..0..0..0..0..0....1..1..1..1..1..1....0..0..0..0..0..0....0..0..0..0..0..0
..2..0..0..0..0..0....2..0..2..0..2..0....0..0..0..0..0..0....0..0..0..0..0..0
..0..2..0..0..0..0....1..1..1..1..1..1....0..0..0..0..0..0....0..1..0..0..0..0

Crossrefs

Cf. A186589.

Sequence in context: A321494 A252103 A074484 * A043666 A180462 A185851

Adjacent sequences: A186580 A186581 A186582 * A186584 A186585 A186586

Keyword

nonn

Author

R. H. Hardin, Feb 24 2011

Status

approved