A206340 Number of (n+1)X6 0..3 arrays with every 2X2 subblock having nonzero determinant and commuting with every horizontal or vertical neighbor

1376, 686, 4007, 2034, 12021, 6090, 36015, 18222, 107997, 54618, 323943, 163806, 971799, 491406, 2915385, 1474206, 8746143, 4422606, 26238417, 13267806, 78715239, 39803406, 236145705, 119410206, 708437103, 358230606, 2125311297

Offset

1,1

Comments

Column 5 of A206343

Links

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

Formula

Empirical: a(n) = a(n-1) +3*a(n-2) -3*a(n-3) for n>14

Example

Some solutions for n=4
..0..1..0..2..0..2....1..2..1..2..1..2....1..1..0..2..0..1....1..0..1..0..2..0
..1..0..1..0..2..0....2..1..2..1..2..1....2..0..1..0..2..0....0..1..0..1..0..2
..0..1..0..1..0..2....1..2..1..2..1..2....0..2..0..1..0..2....1..0..1..0..1..0
..3..0..1..0..1..0....2..1..2..1..2..1....2..0..2..0..1..0....0..1..0..1..0..1
..0..3..0..1..0..1....1..2..1..2..1..2....0..2..0..2..0..1....3..0..1..0..1..2

Crossrefs

Sequence in context: A045131 A365868 A056049 * A056087 A122692 A076760

Adjacent sequences: A206337 A206338 A206339 * A206341 A206342 A206343

Keyword

nonn

Author

R. H. Hardin Feb 06 2012

Status

approved