A208406 Number of nX6 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.

187, 658450, 2540446156, 9810325806914, 37884515848419250, 146298576850884166522, 564960990903273888822194, 2181708996196484728947116626, 8425102300382037852914721068050

Offset: 1

Author

R. H. Hardin Feb 26 2012

Keywords

• nonn

Comments

Column 6 of A208408

Examples

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

Links

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

Formula

Empirical: a(n) = 3934*a(n-1) -280797*a(n-2) +6155504*a(n-3) -54994340*a(n-4) [phone]*a(n-5) -839264272*a(n-6) [phone]*a(n-7) -2573895744*a(n-8) [phone]*a(n-9) -2077701120*a(n-10) [phone]*a(n-11) -191102976*a(n-12) for n>13