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A183503 Number of n X 1 0..3 arrays with no element equal to the sum mod 4 of its horizontal and vertical neighbors. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 1 of A183508.
LINKS
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2011
STATUS
approved

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Last modified July 15 06:58 EDT 2024. Contains 374324 sequences. (Running on oeis4.)