A244177 Number of length n+4 0..2 arrays with no five consecutive elements with pattern ababa or abbba (possibly a=b) and new values 0..2 introduced in 0..2 order.

38, 108, 306, 867, 2457, 6963, 19732, 55918, 158464, 449066, 1272593, 3606359, 10219940, 28961947, 82074294, 232587601, 659122234, 1867864486, 5293278783, 15000445958, 42509262812, 120465580152, 341383384261, 967434971076

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 3*a(n-2) + 4*a(n-3) + 5*a(n-4) + 3*a(n-5) + 2*a(n-6).

Empirical g.f.: x*(38 + 70*x + 84*x^2 + 85*x^3 + 50*x^4 + 27*x^5) / (1 - x - 3*x^2 - 4*x^3 - 5*x^4 - 3*x^5 - 2*x^6). - Colin Barker, Nov 03 2018

Example

Some solutions for n=6:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....0....1....1....0....0....1....0....1....1....0....1....0....0....0....1
..0....1....2....1....1....1....0....1....2....2....1....1....1....1....1....2
..1....0....2....2....0....2....2....2....1....0....2....2....0....0....2....0
..1....2....1....1....0....1....1....2....0....1....1....1....0....1....2....2
..1....1....0....0....0....1....2....1....2....2....1....2....2....1....2....2
..1....0....1....2....2....2....1....0....1....0....0....2....0....0....0....0
..0....1....1....2....2....2....1....1....2....1....1....0....0....2....1....0
..0....0....1....1....1....0....0....1....0....2....0....1....1....0....1....1
..1....0....1....0....1....0....2....1....1....0....0....1....0....2....2....2

Crossrefs

Column 2 of A244185.

Sequence in context: A186439 A044225 A044606 * A251236 A283804 A251229

Adjacent sequences: A244174 A244175 A244176 * A244178 A244179 A244180

Keyword

nonn

Author

R. H. Hardin, Jun 21 2014

Status

approved