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A230726
Number of n X 4 0..5 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value (x(i,j)+1) mod 6, and upper left element zero.
1
0, 2, 30, 396, 6212, 95412, 1459082, 22379112, 343179162, 5262047702, 80687972676, 1237264461260, 18972099054156, 290916616713522, 4460891769710192, 68402949461361234, 1048885241311782830, 16083520658051806236
OFFSET
1,2
LINKS
FORMULA
Empirical: a(n) = 16*a(n-1) - 12*a(n-2) + 87*a(n-3) - 918*a(n-4) + 61*a(n-5) - a(n-6).
Empirical g.f.: 2*x^2*(1 - x)*(1 - 30*x^2 + x^3) / (1 - 16*x + 12*x^2 - 87*x^3 + 918*x^4 - 61*x^5 + x^6). - Colin Barker, Sep 22 2018
EXAMPLE
Some solutions for n=4:
..0..1..0..5....0..1..2..3....0..1..2..1....0..1..2..3....0..1..2..3
..2..3..4..5....0..1..4..3....0..3..2..3....2..3..4..5....2..3..4..5
..2..1..0..5....0..5..4..3....4..5..4..3....2..1..0..3....2..5..0..1
..0..3..4..3....2..3..2..1....0..1..2..1....4..5..4..3....4..3..2..1
CROSSREFS
Column 4 of A230730.
Sequence in context: A231597 A216119 A083446 * A091345 A147682 A211906
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 28 2013
STATUS
approved