A207027 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically

8, 64, 168, 558, 1586, 3726, 9450, 21318, 47518, 104470, 220531, 464202, 957412, 1949906, 3940218, 7868976, 15610980, 30742563, 60142488, 117047084, 226575095, 436635184, 837955970, 1601924662, 3051891570, 5795441060, 10972726928

Offset

1,1

Comments

Row 4 of A207024

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -11*a(n-3) -13*a(n-4) +39*a(n-5) +29*a(n-6) -35*a(n-7) -84*a(n-8) +25*a(n-9) +53*a(n-10) +48*a(n-11) -15*a(n-12) +6*a(n-13) -69*a(n-14) -25*a(n-15) +a(n-16) +54*a(n-17) +2*a(n-18) +16*a(n-19) -12*a(n-20) -6*a(n-21) -15*a(n-22) +6*a(n-23) +3*a(n-25) +a(n-27) -a(n-28)

Example

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

Crossrefs

Sequence in context: A044195 A153808 A207601 * A207172 A207455 A207307

Adjacent sequences: A207024 A207025 A207026 * A207028 A207029 A207030

Keyword

nonn

Author

R. H. Hardin Feb 14 2012

Status

approved