A235843 Number of (n+1) X (1+1) 0..3 arrays with the upper median unequal to the lower median in every 2 X 2 subblock.

156, 1584, 16228, 166816, 1716484, 17668128, 181881988, 1872430816, 19276479364, 198450294432, 2043038387332, 21033017293408, 216534315178372, 2229214808561184, 22949705750645380, 236266598507573728

Offset

1,1

Links

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

Formula

Empirical: a(n) = 14*a(n-1) - 31*a(n-2) - 94*a(n-3) + 192*a(n-4) + 192*a(n-5).

Empirical g.f.: 4*x*(39 - 150*x - 278*x^2 + 848*x^3 + 768*x^4) / (1 - 14*x + 31*x^2 + 94*x^3 - 192*x^4 - 192*x^5). - Colin Barker, Oct 19 2018

Example

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

Crossrefs

Column 1 of A235849.

Sequence in context: A204957 A263305 A235849 * A065699 A263290 A275766

Adjacent sequences: A235840 A235841 A235842 * A235844 A235845 A235846

Keyword

nonn

Author

R. H. Hardin, Jan 16 2014

Status

approved