A236148 Number of (n+1) X (1+1) 0..2 arrays colored with the sets of distinct values in every 2 X 2 subblock.

81, 414, 2148, 11064, 57132, 294648, 1520856, 7845624, 40488216, 208893336, 1077925704, 5561714424, 28698381576, 148076913912, 764063601480, 3942427621752, 20342443076808, 104963700280056, 541598357861448

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 18*a(n-2) + 16*a(n-3) + 12*a(n-4) - 12*a(n-5).

Empirical g.f.: 3*x*(27 + 111*x + 92*x^2 + 56*x^3 - 64*x^4) / (1 - x - 18*x^2 - 16*x^3 - 12*x^4 + 12*x^5). - Colin Barker, Oct 20 2018

Example

Some solutions for n=5:
..0..2....2..2....0..1....1..2....0..0....2..1....2..1....2..1....1..1....0..0
..1..1....2..0....1..1....0..0....0..1....0..2....0..2....2..2....0..0....2..2
..0..1....0..1....0..2....0..2....2..2....2..2....2..0....2..2....2..0....1..0
..2..2....1..1....2..2....1..2....2..2....1..1....0..1....2..1....1..0....1..0
..0..0....1..2....1..2....1..2....1..2....1..0....1..0....1..0....1..1....2..0
..0..0....1..0....0..1....2..0....0..1....1..2....2..2....0..0....2..0....0..0

Crossrefs

Column 1 of A236155.

Sequence in context: A253456 A236155 A253449 * A205986 A206668 A238180

Adjacent sequences: A236145 A236146 A236147 * A236149 A236150 A236151

Keyword

nonn

Author

R. H. Hardin, Jan 19 2014

Status

approved