A207367 Number of nX7 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 0 1 1 vertically.

25, 625, 3025, 14641, 45738, 142884, 353808, 876096, 1869192, 3988009, 7660492, 14714896, 26130832, 46403344, 77513748, 129481641, 205925763, 327501409, 500255371, 764135449, 1128442546, 1666435684, 2391271116, 3431382084

Offset: 1

Author

R. H. Hardin Feb 17 2012

Keywords

• nonn

Comments

Column 7 of A207368

Examples

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

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +8*a(n-2) -18*a(n-3) -27*a(n-4) +72*a(n-5) +48*a(n-6) -168*a(n-7) -42*a(n-8) +252*a(n-9) -252*a(n-11) +42*a(n-12) +168*a(n-13) -48*a(n-14) -72*a(n-15) +27*a(n-16) +18*a(n-17) -8*a(n-18) -2*a(n-19) +a(n-20)