A183503 Number of n X 1 0..3 arrays with no element equal to the sum mod 4 of its horizontal and vertical neighbors.

3, 12, 27, 81, 252, 729, 2187, 6588, 19683, 59049, 177228, 531441, 1594323, 4783212, 14348907, 43046721, 129140892, 387420489, 1162261467, 3486786588, 10460353203, 31381059609, 94143185388, 282429536481, 847288609443, 2541865848012

Offset

1,1

Comments

Column 1 of A183508.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 3*a(n-1) + 3*a(n-3) - 9*a(n-4).

Empirical g.f.: 3*x*(1 + x)*(1 - 3*x^2) / ((1 - 3*x)*(1 - 3*x^3)). - Colin Barker, Mar 29 2018

Example

Some solutions for 3 X 1:
..3....3....3....2....0....3....1....1....2....2....0....0....1....0....2....0
..0....1....1....0....2....2....0....3....1....0....3....3....2....1....3....3
..2....0....3....3....0....0....1....0....0....1....1....2....3....0....0....0

Crossrefs

Cf. A183508.

Sequence in context: A187273 A361847 A009259 * A216713 A133647 A009222

Adjacent sequences: A183500 A183501 A183502 * A183504 A183505 A183506

Keyword

nonn

Author

R. H. Hardin, Jan 05 2011

Status

approved