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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.
1
10, 122, 1985, 32414, 529862, 8662343, 141615905, 2315203034, 37850025182, 618789971363, 10116268804625, 165385509256454, 2703799908891302, 44202989610119183, 722651215442080145, 11814241158484224674
OFFSET
1,1
LINKS
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 03 2013
STATUS
approved