A204071 Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..2 introduced in row major order.

188, 2882, 45056, 706454, 11081828, 173848010, 2727300008, 42785526110, 671213931980, 10529919897938, 165192062569424, 2591512360153766, 40655320900906676, 637795575671145050, 10005657004627715960

Offset: 1

Author

R. H. Hardin, Jan 10 2012

Keywords

• nonn

Comments

Column 3 of A204076.

Examples

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

Links

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

Crossrefs

Cf. A204076.

Formula

Empirical: a(n) = 20*a(n-1) - 73*a(n-2) + 86*a(n-3) - 32*a(n-4).

Empirical g.f.: 2*x*(94 - 439*x + 570*x^2 - 224*x^3) / ((1 - x)*(1 - 19*x + 54*x^2 - 32*x^3)). - Colin Barker, Jun 06 2018