A206342 Number of (n+1)X8 0..3 arrays with every 2X2 subblock having nonzero determinant and commuting with every horizontal or vertical neighbor

4111, 2042, 12005, 6078, 36015, 18258, 108141, 54762, 324087, 163950, 971925, 491514, 2915439, 1474206, 8746143, 4422606, 26238417, 13267806, 78715239, 39803406, 236145705, 119410206, 708437103, 358230606, 2125311297, 1074691806

Offset

1,1

Comments

Column 7 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>16

Example

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

Crossrefs

Sequence in context: A077190 A204530 A204526 * A031828 A205581 A061325

Adjacent sequences: A206339 A206340 A206341 * A206343 A206344 A206345

Keyword

nonn

Author

R. H. Hardin Feb 06 2012

Status

approved