A251203 Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock summing to a nonzero multiple of 2.

40, 180, 816, 3728, 17152, 79424, 369920, 1731840, 8144896, 38458368, 182218752, 865931264, 4125491200, 19697254400, 94217240576, 451363012608, 2165141143552, 10397297147904, 49974875258880, 240389177999360, 1157058166521856

Offset

1,1

Links

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

Formula

Empirical: a(n) = 8*a(n-1) - 12*a(n-2) - 16*a(n-3).

Empirical g.f.: 4*x*(10 - 35*x - 36*x^2) / ((1 - 4*x)*(1 - 4*x - 4*x^2)). - Colin Barker, Nov 26 2018

Example

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

Crossrefs

Column 1 of A251210.

Sequence in context: A327430 A251210 A211497 * A187510 A187379 A077818

Adjacent sequences: A251200 A251201 A251202 * A251204 A251205 A251206

Keyword

nonn

Author

R. H. Hardin, Nov 30 2014

Status

approved