A209808 Number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock having two distinct values, and new values 0..3 introduced in row major order.

34, 302, 2721, 25505, 244208, 2377378, 23398105, 231987361, 2311229272, 23098641162, 231319042937, 2319549963665, 23278778523264, 233749081336914, 2347950341283193, 23589750833899361, 237038455370387400

Offset

1,1

Comments

Column 2 of A209814.

Links

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

Formula

Empirical: a(n) = 17*a(n-1) - 68*a(n-2) - 56*a(n-3) + 397*a(n-4) - 181*a(n-5) - 264*a(n-6) + 108*a(n-7).

Empirical g.f.: x*(34 - 276*x - 101*x^2 + 1688*x^3 - 935*x^4 - 1182*x^5 + 504*x^6) / ((1 - 6*x - 3*x^2 + 2*x^3)*(1 - 11*x + 5*x^2 + 51*x^3 - 54*x^4)). - Colin Barker, Jul 13 2018

Example

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

Crossrefs

Cf. A209814.

Sequence in context: A156531 A220565 A230803 * A160146 A101092 A233061

Adjacent sequences: A209805 A209806 A209807 * A209809 A209810 A209811

Keyword

nonn

Author

R. H. Hardin, Mar 13 2012

Status

approved