A207662 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 1 0 0 vertically.

9, 81, 198, 870, 3358, 12040, 47320, 182192, 676396, 2611234, 9988846, 37623896, 144190134, 550120868, 2085006194, 7964169488, 30353664882, 115358871282, 439963965434, 1676145338780, 6377929104862, 24307253165970, 92589759354554

Offset: 1

Author

R. H. Hardin Feb 19 2012

Keywords

• nonn

Comments

Row 4 of A207661

Examples

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

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-2) +45*a(n-3) -13*a(n-4) -13*a(n-5) -450*a(n-6) -7*a(n-7) +119*a(n-8) +1406*a(n-9) +299*a(n-10) -560*a(n-11) -796*a(n-12) -402*a(n-13) -232*a(n-14) -1784*a(n-15) +797*a(n-16) +1473*a(n-17) +418*a(n-18) -221*a(n-19) -95*a(n-20) +35*a(n-21) -234*a(n-22) -9*a(n-23) +45*a(n-24) +4*a(n-25) -3*a(n-26) for n>29