A206873 Number of 4Xn 0..1 arrays avoiding 0 0 0 horizontally and 1 0 1 vertically.

12, 144, 889, 7675, 63866, 502864, 4108471, 33311703, 269021206, 2180747052, 17657728229, 142945674729, 1157610400394, 9373284938378, 75896278735065, 614558095591053, 4976204942982610, 40293442480994080, 326265843009762463

Offset: 1

Author

R. H. Hardin Feb 13 2012

Keywords

• nonn

Comments

Row 4 of A206871

Examples

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

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +22*a(n-2) +195*a(n-3) +237*a(n-4) +211*a(n-5) -2946*a(n-6) -1034*a(n-7) -4204*a(n-8) +13726*a(n-9) +2298*a(n-10) +9852*a(n-11) -18860*a(n-12) -5516*a(n-13) -8002*a(n-14) +9398*a(n-15) +3229*a(n-16) +2616*a(n-17) -2128*a(n-18) -839*a(n-19) -433*a(n-20) +161*a(n-21) +68*a(n-22) +28*a(n-23)