A251383 Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock summing to 2 3 4 5 or 6.

71, 571, 4585, 36825, 295759, 2375387, 19077905, 153224073, 1230618167, 9883701979, 79380889561, 637547109465, 5120455553407, 41124906199355, 330294422491457, 2652757552810569, 21305605407779879, 171115834280100859

Offset

1,1

Links

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

Formula

Empirical: a(n) = 8*a(n-1) + a(n-2) - 6*a(n-3).

Empirical g.f.: x*(71 + 3*x - 54*x^2) / (1 - 8*x - x^2 + 6*x^3). - Colin Barker, Nov 29 2018

Example

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

Crossrefs

Column 1 of A251390.

Sequence in context: A209960 A209953 A251390 * A180327 A201039 A142674

Adjacent sequences: A251380 A251381 A251382 * A251384 A251385 A251386

Keyword

nonn

Author

R. H. Hardin, Dec 01 2014

Status

approved