A222919 Number of n X 1 0..4 arrays with no three equal values in a row horizontally or vertically, and new values 0..4 introduced in row major order.

1, 2, 4, 12, 41, 158, 663, 2944, 13537, 63551, 301968, 1444795, 6940099, 33411718, 161058633, 776930015, 3749357128, 18098055047, 87370273487, 421820387606, 2036618058597, 9833358788859, 47478828272736, 229245800095323

Offset: 1

Author

R. H. Hardin, Mar 09 2013

Keywords

• nonn

Comments

Column 1 of A222924.

Examples

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

Links

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

Crossrefs

Cf. A222924.

Formula

Empirical: a(n) = 7*a(n-1) - 7*a(n-2) - 20*a(n-3) + 10*a(n-4) + 24*a(n-5) + 8*a(n-6) for n>8.

Empirical g.f.: x*(1 + x)*(1 - 6*x + 3*x^2 + 15*x^3 - 9*x^5 - 3*x^6) / ((1 - x - x^2)*(1 - 2*x - 2*x^2)*(1 - 4*x - 4*x^2)). - Colin Barker, Mar 16 2018