A233068 Number of n X 3 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, antidiagonally or vertically, top left element zero, and 1 appearing before 2 in row major order.

5, 50, 582, 6854, 80811, 952869, 11235652, 132484030, 1562171807, 18420188169, 217199754056, 2561088558394, 30198812298187, 356086188910685, 4198753668883532, 49509171995392534, 583782308982449751

Offset

1,1

Links

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

Formula

Empirical: a(n) = 14*a(n-1) - 28*a(n-2) + 24*a(n-3) - 11*a(n-4) + 2*a(n-5) for n>6.

Empirical g.f.: x*(5 - 20*x + 22*x^2 - 14*x^3 + 6*x^4 - x^5) / ((1 - x)*(1 - 13*x + 15*x^2 - 9*x^3 + 2*x^4)). - Colin Barker, Oct 07 2018

Example

Some solutions for n=5:
..0..0..1....0..1..1....0..1..0....0..0..1....0..1..3....0..1..0....0..1..1
..0..0..1....1..1..3....1..1..0....1..0..0....1..3..1....1..1..1....1..0..1
..0..0..0....3..3..1....1..0..0....1..0..2....3..3..3....3..3..1....0..1..1
..2..2..2....1..1..1....1..0..1....0..2..2....3..2..2....3..3..1....1..3..3
..3..2..3....3..1..0....1..0..0....0..2..3....2..3..2....3..3..3....3..3..2

Crossrefs

Column 3 of A233073.

Sequence in context: A286974 A199762 A078244 * A237020 A156058 A232997

Adjacent sequences: A233065 A233066 A233067 * A233069 A233070 A233071

Keyword

nonn

Author

R. H. Hardin, Dec 03 2013

Status

approved