A208410 Number of 3 X n 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.

5, 187, 10682, 658450, 40883360, 2540446156, 157873031498, 9810914663050, 609693293454056, 37889020302613060, 2354590230800815490, 146324584692741696562, 9093252748398554214416, 565094688091663621180732

Offset: 1

Author

R. H. Hardin, Feb 26 2012

Keywords

• nonn

Comments

Row 3 of A208408.

Examples

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

Links

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

Crossrefs

Cf. A208408.

Formula

Empirical: a(n) = 62*a(n-1) + 39*a(n-2) - 1790*a(n-3) - 4703*a(n-4) - 1254*a(n-5) + 3249*a(n-6) + 918*a(n-7) - 648*a(n-8) for n>10.

Empirical g.f.: x*(1 + x)*(2 - 23*x - 3*x^2 + 22*x^3 + 8*x^4) / ((1 - 3*x - 2*x^2)*(1 - 15*x - 12*x^2)). - Colin Barker, Jul 02 2018