A186478 Number of (n+1)X6 0..3 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors

4895, 3442, 20224, 25633, 107353, 108025, 433513, 479785, 1793817, 2226665, 7478693, 10225073, 31371137, 46298817, 132181633, 207648469, 559418905, 924724441, 2376589225, 4095459817, 10129319461, 18060113137, 43291468321

Offset

1,1

Comments

Column 5 of A186482

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=2*a(n-1)+2*a(n-2)-6*a(n-3)+6*a(n-4)-3*a(n-5) for n>16

Example

Some solutions for 3X6
..1..0..0..0..2..1....0..1..0..1..0..1....0..0..0..0..3..0....2..0..1..0..0..0
..1..0..0..0..0..2....3..0..1..0..1..1....0..0..0..0..0..3....0..2..0..1..0..0
..0..1..0..0..0..0....0..3..0..1..1..2....0..0..0..0..0..0....3..0..2..0..1..1

Crossrefs

Sequence in context: A126704 A374804 A251325 * A220059 A339939 A321146

Adjacent sequences: A186475 A186476 A186477 * A186479 A186480 A186481

Keyword

nonn

Author

R. H. Hardin Feb 22 2011

Status

approved