A209890 Number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having two distinct values, and new values 0..2 introduced in row major order.

7, 34, 164, 792, 3824, 18464, 89152, 430464, 2078464, 10035712, 48456704, 233969664, 1129705472, 5454700544, 26337624064, 127169298432, 614027689984, 2964787953664, 14315262574592, 69120202113024, 333741858750464

Offset

1,1

Comments

Column 1 of A209897.

Links

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

Formula

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

Empirical G.f.: x*(7+6*x)/(1-4*x-4*x^2). [Colin Barker, Mar 15 2012]

Example

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

Crossrefs

Sequence in context: A032206 A124466 A055271 * A027209 A209807 A351588

Adjacent sequences: A209887 A209888 A209889 * A209891 A209892 A209893

Keyword

nonn

Author

R. H. Hardin, Mar 14 2012

Status

approved