A205305 Number of nX3 0..3 arrays with no occurrence of three equal elements in a row horizontally or vertically, and new values 0..3 introduced in row major order.

4, 159, 7445, 381958, 19490790, 996536552, 50933680120, 2603456557653, 133072628448179, 6801873967993408, 347670725973943044, 17770830778194675356, 908337669425005770376, 46428742540607711341143

Offset: 1

Author

R. H. Hardin Jan 25 2012

Keywords

• nonn

Comments

Column 3 of A205310

Examples

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

Links

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

Formula

Empirical: a(n) = 45*a(n-1) +360*a(n-2) -2443*a(n-3) +752*a(n-4) +1861*a(n-5) +17330*a(n-6) +3931*a(n-7) -55696*a(n-8) -6621*a(n-9) +28764*a(n-10) -5265*a(n-11) -9477*a(n-12) +1080*a(n-13) +1080*a(n-14)