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A238721 Number of n X 3 0..2 arrays with no element equal to the sum modulo 3 of elements to its left or elements above it. 1
4, 10, 40, 86, 336, 704, 2704, 5660, 21504, 45176, 170464, 359400, 1350272, 2854496, 10694912, 22650672, 84716224, 179637056, 671110848, 1424180800, 5316817088, 11288673952, 42124029504, 89466980000, 333750473152, 708999096096, 2644373950784, 5618300601952 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 17*a(n-2) -96*a(n-4) +210*a(n-6) -152*a(n-8).
EXAMPLE
Some solutions for n=5:
..1..2..1....2..1..1....2..1..2....2..1..1....1..2..1....1..2..1....2..1..1
..2..1..2....1..0..2....1..2..1....1..2..2....2..0..0....2..0..0....1..2..2
..1..2..1....2..0..1....1..2..2....1..2..2....2..0..0....1..0..2....2..1..1
..2..0..0....1..0..2....2..0..1....2..1..1....1..0..2....2..0..1....1..0..2
..2..1..2....1..2..1....2..1..2....1..2..1....2..0..1....2..1..2....1..0..2
CROSSREFS
Column 3 of A238726.
Sequence in context: A038168 A186337 A100307 * A077811 A136855 A136860
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 03 2014
STATUS
approved

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Last modified June 21 13:19 EDT 2024. Contains 373544 sequences. (Running on oeis4.)