A207113 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically

8, 64, 200, 643, 1835, 4534, 11511, 27012, 62814, 144676, 325111, 733469, 1635998, 3639007, 8091148, 17910532, 39681294, 87775953, 194044225, 429056388, 947971827, 2094875648, 4628499152, 10225059546, 22590584639, 49903794405

Offset

1,1

Comments

Row 4 of A207111

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +5*a(n-2) -4*a(n-3) -23*a(n-4) +4*a(n-5) +40*a(n-6) +19*a(n-7) -38*a(n-8) -28*a(n-9) -a(n-11) +13*a(n-12) +38*a(n-13) +15*a(n-14) -31*a(n-15) -24*a(n-16) -2*a(n-17) +9*a(n-18) +6*a(n-19) +6*a(n-20) -2*a(n-21) -3*a(n-22) -a(n-23) +a(n-24)

Example

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

Crossrefs

Sequence in context: A207172 A207455 A207307 * A207393 A207940 A016743

Adjacent sequences: A207110 A207111 A207112 * A207114 A207115 A207116

Keyword

nonn

Author

R. H. Hardin Feb 15 2012

Status

approved