A233084 Number of 3 X n 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 in row major order.

10, 122, 1985, 32414, 529862, 8662343, 141615905, 2315203034, 37850025182, 618789971363, 10116268804625, 165385509256454, 2703799908891302, 44202989610119183, 722651215442080145, 11814241158484224674

Offset

1,1

Links

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

Formula

Empirical: a(n) = 19*a(n-1) - 45*a(n-2) + 27*a(n-3) for n>5.

Empirical g.f.: x*(10 - 68*x + 117*x^2 - 81*x^3 + 27*x^4) / ((1 - x)*(1 - 18*x + 27*x^2)). - Colin Barker, Oct 07 2018

Example

Some solutions for n=4:
..0..1..0..2....0..1..1..3....0..1..3..1....0..1..3..2....0..1..0..2
..1..0..0..0....1..1..3..3....0..1..3..3....1..3..2..3....0..0..0..0
..1..0..0..2....1..3..3..2....3..3..1..1....3..3..3..2....1..0..1..0

Crossrefs

Row 3 of A233082.

Sequence in context: A098309 A056116 A246643 * A081784 A239760 A296190

Adjacent sequences: A233081 A233082 A233083 * A233085 A233086 A233087

Keyword

nonn

Author

R. H. Hardin, Dec 03 2013

Status

approved