A205219 Number of (n+1)X2 0..1 arrays with the number of equal 2X2 subblock diagonal pairs and equal antidiagonal pairs differing from each horizontal or vertical neighbor, and new values 0..1 introduced in row major order

8, 20, 52, 132, 340, 868, 2228, 5700, 14612, 37412, 95860, 245508, 628948, 1610980, 4126772, 10570692, 27077780, 69360548, 177671668, 455113860, 1165800532, 2986255972, 7649458100, 19594481988, 50192314388, 128570242340, 329339499892

Offset

1,1

Comments

Column 1 of A205226

Links

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

Formula

Empirical: a(n) = a(n-1) +4*a(n-2).

Empirical g.f.: 4*x*(2+3*x)/(1-x-4*x^2). - R. J. Mathar, Jun 18 2013

Example

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

Crossrefs

Sequence in context: A107816 A361073 A361215 * A232401 A036835 A295933

Adjacent sequences: A205216 A205217 A205218 * A205220 A205221 A205222

Keyword

nonn

Author

R. H. Hardin Jan 23 2012

Status

approved