A206695 Number of nX3 0..2 arrays avoiding the pattern z-2 z-1 z in any row or column.

26, 676, 15712, 363465, 8366690, 192513201, 4428597297, 101873060353, 2343406014665, 53905733689480, 1240001271788197, 28523922980667486, 656139776848417214, 15093274671338487633, 347192698846268632122

Offset: 1

Author

R. H. Hardin Feb 11 2012

Keywords

• nonn

Comments

Column 3 of A206700

Examples

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

Links

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

Formula

Empirical: a(n) = 29*a(n-1) -84*a(n-2) -1570*a(n-3) +6618*a(n-4) +28026*a(n-5) -136815*a(n-6) -145173*a(n-7) +1005714*a(n-8) -486446*a(n-9) -1842056*a(n-10) +1805556*a(n-11) +1069186*a(n-12) -1763040*a(n-13) +27675*a(n-14) +626313*a(n-15) -148782*a(n-16) -66294*a(n-17) +19454*a(n-18) +2708*a(n-19) -849*a(n-20) -37*a(n-21) +12*a(n-22)