A251492 Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock summing to 4 5 6 7 or 8.

186, 2270, 27844, 341718, 4194002, 51474508, 631765770, 7753896830, 95166467620, 1168013551254, 14335465950002, 175944520325356, 2159432720260170, 26503523182815518, 325287625083982468, 3992376345699782742

Offset

1,1

Links

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

Formula

Empirical: a(n) = 13*a(n-1) - 5*a(n-2) - 52*a(n-3) + 48*a(n-4).

Empirical g.f.: 2*x*(93 - 74*x - 368*x^2 + 384*x^3) / (1 - 13*x + 5*x^2 + 52*x^3 - 48*x^4). - Colin Barker, Nov 29 2018

Example

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

Crossrefs

Column 1 of A251499.

Sequence in context: A200199 A364859 A251499 * A289301 A147817 A318270

Adjacent sequences: A251489 A251490 A251491 * A251493 A251494 A251495

Keyword

nonn

Author

R. H. Hardin, Dec 03 2014

Status

approved