A210260 Number of (n+1) X 2 0..3 arrays containing all values 0..3 with every 2 X 2 subblock having three distinct values, and new values 0..3 introduced in row major order.

0, 29, 400, 4298, 42520, 406580, 3828928, 35804264, 333688864, 3104980304, 28869996928, 268334928032, 2493631919488, 23171354998592, 215304570112000, 2000537970249344, 18588159494998528, 172712625468359936

Offset

1,2

Comments

Column 1 of A210267.

Links

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

Formula

Empirical: a(n) = 12*a(n-1) - 18*a(n-2) - 64*a(n-3) - 24*a(n-4).

Empirical g.f.: x^2*(29 + 52*x + 20*x^2) / ((1 - 4*x - 2*x^2)*(1 - 8*x - 12*x^2)). - Colin Barker, Jul 15 2018

Example

Some solutions for n=4:
..0..1....0..0....0..0....0..1....0..0....0..0....0..0....0..0....0..1....0..0
..2..1....1..2....1..2....0..2....1..2....1..2....1..2....1..2....0..2....1..2
..3..1....0..1....1..3....1..1....0..2....1..3....1..0....3..1....1..1....3..2
..0..1....1..2....1..2....2..3....3..3....2..1....1..2....1..2....3..0....0..2
..3..3....3..3....3..2....2..0....0..1....2..3....2..3....0..1....1..0....0..3

Crossrefs

Cf. A210267.

Sequence in context: A160298 A077508 A077514 * A010945 A022624 A042630

Adjacent sequences: A210257 A210258 A210259 * A210261 A210262 A210263

Keyword

nonn

Author

R. H. Hardin, Mar 19 2012

Status

approved