A206208 Number of (n+1) X 2 0..2 arrays with every 2 X 3 or 3 X 2 subblock having exactly two equal edges, and new values 0..2 introduced in row major order.

14, 45, 162, 594, 2268, 8802, 34236, 133974, 525636, 2062530, 8099676, 31820742, 125010756, 491167314, 1929919068, 7583091318, 29796066756, 117078181218, 460036667484, 1807630002342, 7102763113284, 27909047936754, 109663668632412

Offset

1,1

Comments

Column 1 of A206215.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - a(n-2) + 12*a(n-3) - 36*a(n-4) for n>5.

Empirical g.f.: x*(14 - 11*x - 4*x^2 - 177*x^3 + 18*x^4) / ((1 - 2*x)*(1 - 2*x - 3*x^2 - 18*x^3)). - Colin Barker, Jun 14 2018

Example

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

Crossrefs

Cf. A206215.

Sequence in context: A232791 A243384 A242579 * A328245 A039368 A043191

Adjacent sequences: A206205 A206206 A206207 * A206209 A206210 A206211

Keyword

nonn

Author

R. H. Hardin, Feb 04 2012

Status

approved