A207483 Number of n X 3 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 1 and 1 1 0 vertically.

6, 36, 82, 177, 408, 942, 2233, 5348, 12994, 31873, 78920, 196862, 494329, 1248164, 3166802, 8067793, 20626904, 52898478, 136020345, 350558596, 905277122, 2341815073, 6067027656, 15738638142, 40874569785, 106260279044, 276481264786

Offset

1,1

Comments

Column 3 of A207488.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) - 13*a(n-2) - 10*a(n-3) + 48*a(n-4) - 16*a(n-5) - 47*a(n-6) + 25*a(n-7) + 13*a(n-8) - 6*a(n-9) for n>10.

Empirical g.f.: x*(6 - 6*x - 92*x^2 + 131*x^3 + 307*x^4 - 425*x^5 - 365*x^6 + 401*x^7 + 131*x^8 - 82*x^9) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - 3*x + x^2)*(1 - x - x^2)*(1 - x - 3*x^2)). - Colin Barker, Mar 05 2018

Example

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

Crossrefs

Cf. A207488.

Sequence in context: A208103 A207724 A208689 * A207264 A207270 A207763

Adjacent sequences: A207480 A207481 A207482 * A207484 A207485 A207486

Keyword

nonn

Author

R. H. Hardin, Feb 18 2012

Status

approved