A184370 1/3 the number of (n+1)X4 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

1107, 49235, 2167173, 95528423, 4210059673, 185547841629, 8177524177277, 360402692568245, 15883791500540967, 700035935394350709, 30852225032929689819, 1359729896274471875219, 59926484677950059719491

Offset: 1

Author

R. H. Hardin Jan 12 2011

Keywords

• nonn

Comments

Column 3 of A184376

Examples

			Some solutions for 3X4 with a(1,1)=0
..0..0..0..2....0..1..1..1....0..1..0..1....0..0..2..1....0..1..1..1
..1..2..2..2....0..1..1..0....0..1..0..1....1..0..2..1....2..1..2..0
..0..2..2..0....2..2..2..2....1..1..0..0....1..1..2..1....0..0..0..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=38*a(n-1)+302*a(n-2)-1368*a(n-3)-6770*a(n-4)+12666*a(n-5)-575*a(n-6)-5790*a(n-7)+828*a(n-8)+648*a(n-9)