A241133 Number of n X 2 0..2 arrays with no element equal to the same number of vertical neighbors as horizontal neighbors, with new values 0..2 introduced in row major order.

1, 2, 5, 17, 56, 195, 691, 2476, 8941, 32393, 117632, 427635, 1555643, 5661060, 20604893, 75004865, 273044808, 994013923, 3618750915, 13174348572, 47962513037, 174612764153, 635697854288, 2314333217939, 8425607885003

Offset

1,2

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 2*a(n-2) - 11*a(n-3) - 6*a(n-4) + 8*a(n-5) for n>6.

Empirical g.f.: x*(1 - x)*(1 - x - 6*x^2 - 2*x^3 + 4*x^4) / ((1 - 2*x)*(1 - 2*x - 6*x^2 - x^3 + 4*x^4)). - Colin Barker, Oct 29 2018

Example

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

Crossrefs

Column 2 of A241138.

Sequence in context: A159866 A042671 A180148 * A148410 A190531 A148411

Adjacent sequences: A241130 A241131 A241132 * A241134 A241135 A241136

Keyword

nonn

Author

R. H. Hardin, Apr 16 2014

Status

approved