A186562 Number of (n+2) X 5 0..2 arrays with every 3 X 3 subblock commuting with each horizontal and vertical neighbor 3 X 3 subblock.

2917, 401, 1399, 3421, 4807, 5605, 6511, 8029, 11647, 19237, 31623, 49805, 77743, 118309, 177703, 271789, 415903, 634037, 977431, 1502013, 2293423, 3523525, 5404231, 8254861, 12669663, 19434837, 29722679, 45599069, 69937615, 107022757

Offset

1,1

Comments

Column 3 of A186568.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) - a(n-2) + 2*a(n-3) - 4*a(n-4) + 2*a(n-5) + 2*a(n-6) - 2*a(n-7) for n>11.

Empirical g.f.: x*(2917 - 5433*x + 3514*x^2 - 4810*x^3 + 10230*x^4 - 7616*x^5 - 7774*x^6 + 6916*x^7 + 1280*x^8 - 288*x^9 + 800*x^10) / ((1 - x)*(1 - x - 2*x^3 + 2*x^4 - 2*x^6)). - Colin Barker, Apr 18 2018

Example

Some solutions for 4 X 5:
..0..0..0..0..1....0..0..0..0..0....0..0..0..0..2....0..0..0..0..2
..0..0..0..0..1....0..0..0..0..0....0..0..0..0..2....0..0..0..0..0
..1..0..0..0..1....0..0..0..0..0....0..0..0..0..2....0..0..0..0..0
..1..0..0..0..1....1..1..1..1..1....1..0..0..0..2....2..2..0..0..0

Crossrefs

Cf. A186568.

Sequence in context: A183360 A209046 A209018 * A157935 A081634 A358879

Adjacent sequences: A186559 A186560 A186561 * A186563 A186564 A186565

Keyword

nonn

Author

R. H. Hardin, Feb 23 2011

Status

approved