A185925 Number of (n+1) X 2 0..3 arrays with no 2 X 2 subblock trace equal to any horizontal or vertical neighbor 2 X 2 subblock trace.

256, 3392, 45184, 601280, 8003200, 106519232, 1417744768, 18869769920, 251151368320, 3342753765056, 44491111274368, 592164151358144, 7881537994012288, 104901049688771264, 1396203410850909568

Offset

1,1

Comments

Column 1 of A185933.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) + 81*a(n-2) + 206*a(n-3) + 144*a(n-4).

Empirical g.f.: 64*x*(4 + 29*x + 64*x^2 + 42*x^3) / (1 - 6*x - 81*x^2 - 206*x^3 - 144*x^4). - Colin Barker, Apr 17 2018

Example

Some solutions for 3 X 2:
..3..0....1..2....0..3....0..0....1..1....0..3....2..2....0..0....0..1....0..3
..3..2....3..2....3..2....3..2....2..0....1..1....3..0....2..3....3..1....3..0
..0..0....3..3....1..1....2..0....1..3....2..3....0..0....2..0....3..0....0..3

Crossrefs

Cf. A185933.

Sequence in context: A185575 A185933 A185572 * A205281 A185923 A185919

Adjacent sequences: A185922 A185923 A185924 * A185926 A185927 A185928

Keyword

nonn

Author

R. H. Hardin, Feb 06 2011

Status

approved