A207348 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 0 and 1 1 1 vertically.

10, 100, 292, 828, 2190, 5290, 12292, 27978, 62574, 136978, 298386, 642668, 1375596, 2932342, 6217164, 13153676, 27743768, 58404696, 122773834, 257696786, 540439948, 1132381262, 2371176338, 4962720854, 10382009670, 21712572508

Offset: 1

Author

R. H. Hardin Feb 17 2012

Keywords

• nonn

Comments

Row 4 of A207346

Examples

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

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +3*a(n-2) +a(n-3) -16*a(n-4) -5*a(n-5) -2*a(n-6) +38*a(n-7) +8*a(n-8) +26*a(n-9) -59*a(n-10) +12*a(n-11) -61*a(n-12) +55*a(n-13) -57*a(n-14) +59*a(n-15) -62*a(n-16) +61*a(n-17) -41*a(n-18) +48*a(n-19) -31*a(n-20) +19*a(n-21) -20*a(n-22) +7*a(n-23) -5*a(n-24) +4*a(n-25) +a(n-27) for n>28