A223056 Number of n X 2 0..3 arrays with all horizontally or vertically connected equal values in a straight line, and new values 0..3 introduced in row major order.

2, 10, 114, 1473, 19360, 255045, 3361024, 44294253, 583749160, 7693175205, 101387647984, 1336178514333, 17609374162360, 232072328089365, 3058459941439744, 40307163247443213, 531204410117077960

Offset: 1

Author

R. H. Hardin, Mar 13 2013

Keywords

• nonn

Comments

Column 2 of A223062.

Examples

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

Links

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

Crossrefs

Cf. A223062.

Formula

Empirical: a(n) = 18*a(n-1) - 71*a(n-2) + 102*a(n-3) - 48*a(n-4) for n>5.

Empirical g.f.: x*(2 - 26*x + 76*x^2 - 73*x^3 + 16*x^4) / ((1 - x)*(1 - 2*x)*(1 - 15*x + 24*x^2)). - Colin Barker, Aug 16 2018