A233141 Number of n X 2 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally, antidiagonally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.

2, 16, 225, 3727, 65120, 1158334, 20726079, 371568349, 6665506622, 119595908140, 2145992981277, 38507882245867, 690993582249116, 12399363162575962, 222497465035339899, 3992554551056534713, 71643481793789018234

Offset

1,1

Links

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

Formula

Empirical: a(n) = 25*a(n-1) - 134*a(n-2) + 134*a(n-3) - 25*a(n-4) +a(n-5).

Empirical g.f.: x*(2 - 34*x + 93*x^2 - 22*x^3 + x^4) / ((1 - x)*(1 - 18*x + x^2)*(1 - 6*x + x^2)). - Colin Barker, Oct 08 2018

Example

Some solutions for n=5:
..0..1....0..0....0..0....0..1....0..1....0..1....0..0....0..1....0..1....0..1
..2..1....1..1....1..2....2..2....0..1....1..0....1..2....2..0....2..5....0..2
..2..2....2..1....5..4....1..2....0..1....2..0....0..2....2..1....5..5....4..2
..1..2....5..1....3..3....0..1....0..2....4..0....0..0....5..1....2..2....5..2
..2..1....1..0....4..5....3..5....1..1....4..2....3..0....2..1....2..5....2..1

Crossrefs

Column 2 of A233147.

Sequence in context: A188844 A187657 A047657 * A223631 A188500 A188515

Adjacent sequences: A233138 A233139 A233140 * A233142 A233143 A233144

Keyword

nonn

Author

R. H. Hardin, Dec 04 2013

Status

approved