A239150 Number of (n+1) X (1+1) 0..3 arrays with no element equal to all horizontal neighbors or unequal to all vertical neighbors, and new values 0..3 introduced in row major order.

1, 1, 7, 17, 96, 340, 1639, 6623, 29843, 126163, 554310, 2380524, 10363965, 44756085, 194216303, 840357677, 3642433780, 15771490916, 68331367227, 295943443667, 1282011757819, 5552887116543, 24053558944522, 104188496250108

Offset: 1

Author

R. H. Hardin, Mar 11 2014

Keywords

• nonn

Examples

			Some solutions for n=5:
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
..0..2....1..2....2..0....2..1....2..1....1..0....2..0....2..1....2..0....2..0
..0..2....1..2....2..0....2..0....2..1....1..0....2..0....2..1....2..0....2..0
..2..0....1..3....3..0....2..0....1..3....1..0....1..0....3..1....0..1....3..2
..2..0....1..3....3..0....2..0....1..3....1..0....1..0....3..1....0..1....3..2
		

Links

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

Crossrefs

Column 1 of A239155.

Formula

Empirical: a(n) = 4*a(n-1) + 7*a(n-2) - 26*a(n-3) + 5*a(n-4) + 14*a(n-5).

Empirical g.f.: x*(1 - 3*x - 4*x^2 + 8*x^3) / ((1 - x - x^2)*(1 - 3*x - 9*x^2 + 14*x^3)).