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A230331 Number of n X 2 0..2 arrays x(i,j) with each element horizontally, vertically or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero. 1
0, 6, 34, 218, 1386, 8810, 56010, 356074, 2263690, 14391082, 91489226, 581629546, 3697625866, 23507122602, 149443138122, 950063174890, 6039889469834, 38397725300778, 244107994962122, 1551881335096170, 9865861536380938 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) + 8*a(n-2) + 4*a(n-3).
Empirical g.f.: 2*x^2*(3 + 2*x) / (1 - 5*x - 8*x^2 - 4*x^3). - Colin Barker, Sep 21 2018
EXAMPLE
Some solutions for n=3.
..0..2....0..1....0..1....0..2....0..0....0..1....0..0....0..0....0..2....0..1
..1..0....2..0....2..1....1..2....1..2....1..2....1..0....1..0....1..0....0..2
..0..2....1..2....2..0....0..1....0..2....0..2....2..2....2..1....2..2....1..1
CROSSREFS
Column 2 of A230337.
Sequence in context: A184185 A216317 A370324 * A267242 A197436 A334787
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 16 2013
STATUS
approved

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Last modified February 24 13:41 EST 2024. Contains 370303 sequences. (Running on oeis4.)