A233156 Number of 3 X n 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally or antidiagonally.

27, 96, 432, 1944, 8856, 40392, 184248, 840456, 3833784, 17488008, 79772472, 363886344, 1659886776, 7571661192, 34538532408, 157549339656, 718669633464, 3278249488008, 14953908173112, 68213041889544, 311157393101496

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-1) - 2*a(n-2) for n>4.

Empirical g.f.: 3*x*(9 - 13*x + 2*x^2 - 8*x^3) / (1 - 5*x + 2*x^2). - Colin Barker, Oct 09 2018

Example

Some solutions for n=5:
..1..0..0..0..1....1..0..1..0..1....0..0..0..1..2....0..1..0..0..1
..0..0..0..0..1....0..0..1..0..1....0..1..2..2..2....0..0..1..0..1
..0..0..1..0..1....1..2..1..0..1....0..1..2..2..2....0..0..0..0..1

Crossrefs

Row 3 of A233155.

Sequence in context: A078183 A072252 A154041 * A118615 A197619 A033659

Adjacent sequences: A233153 A233154 A233155 * A233157 A233158 A233159

Keyword

nonn

Author

R. H. Hardin, Dec 05 2013

Status

approved