A185859 1/128 the number of (n+2) X 4 binary arrays with no 3 X 3 subblock trace equal to any horizontal or vertical neighbor 3 X 3 subblock trace.

22, 164, 1254, 9604, 73542, 563180, 4312662, 33025492, 252901110, 1936659260, 14830481526, 113568392452, 869680280982, 6659809438220, 50999270878806, 390540554136916, 2990668706374134, 22901845251766748, 175377003214493814

Offset

1,1

Comments

Column 2 of A185866.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) + 17*a(n-2) - 36*a(n-3) + 24*a(n-4) - 6*a(n-5).

Empirical g.f.: 2*x*(11 + 16*x - 52*x^2 + 42*x^3 - 12*x^4) / (1 - 6*x - 17*x^2 + 36*x^3 - 24*x^4 + 6*x^5). - Colin Barker, Apr 17 2018

Example

Some solutions for 6 X 4:
..0..0..0..1....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..1..1..0....0..1..0..0....0..0..1..0....1..1..1..1....1..0..0..0
..1..1..0..1....1..0..1..0....1..0..0..0....0..1..0..1....0..0..0..1
..0..0..1..0....1..0..0..0....0..1..1..0....0..0..0..0....0..1..1..0
..0..0..0..1....1..1..0..0....1..0..1..0....1..0..0..1....0..0..0..1
..1..0..0..1....1..0..0..1....0..1..1..1....1..0..1..0....1..1..0..0

Crossrefs

Cf. A185866.

Sequence in context: A223913 A189416 A224185 * A173393 A141306 A067561

Adjacent sequences: A185856 A185857 A185858 * A185860 A185861 A185862

Keyword

nonn

Author

R. H. Hardin, Feb 05 2011

Status

approved