A197102 Half the number of n X 1 0..3 arrays with no element equal to the average of its horizontal and vertical neighbors.

2, 6, 16, 61, 212, 753, 2661, 9415, 33302, 117802, 416703, 1474018, 5214089, 18443961, 65242401, 230783990, 816359440, 2887733833, 10214871388, 36133384697, 127815754113, 452126672783, 1599321849338, 5657331300590

Offset

1,1

Comments

Column 1 of A197109.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

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

Empirical g.f.: x*(2 + 2*x - 6*x^2 - 7*x^3 + 8*x^5) / (1 - 2*x - 5*x^2 - 3*x^3 + 4*x^4 + 4*x^5). - Colin Barker, May 11 2018

Example

Some solutions for 4 X 4:
..0....0....0....0....1....1....0....1....1....1....1....0....0....0....1....1
..1....1....3....3....0....0....3....3....0....0....2....1....3....1....0....2
..1....0....3....2....3....0....3....0....0....1....0....1....0....0....3....0
..0....3....1....0....2....2....2....2....1....0....2....3....1....2....0....1

Crossrefs

Cf. A197109.

Sequence in context: A027742 A324062 A033301 * A093113 A150030 A150031

Adjacent sequences: A197099 A197100 A197101 * A197103 A197104 A197105

Keyword

nonn

Author

R. H. Hardin, Oct 10 2011

Status

approved