A206341 Number of (n+1)X7 0..3 arrays with every 2X2 subblock having nonzero determinant and commuting with every horizontal or vertical neighbor

880, 1589, 2030, 4711, 6090, 14181, 18258, 42351, 54654, 126861, 163842, 380391, 491406, 1141143, 1474206, 3423417, 4422606, 10270239, 13267806, 30810705, 39803406, 92432103, 119410206, 277296297, 358230606, 831888879, 1074691806

Offset

1,1

Comments

Column 6 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>15

Example

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

Crossrefs

Sequence in context: A190030 A118799 A050424 * A357495 A024393 A006052

Adjacent sequences: A206338 A206339 A206340 * A206342 A206343 A206344

Keyword

nonn

Author

R. H. Hardin Feb 06 2012

Status

approved