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A233213
Number of n X 4 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.
1
23, 7222, 3054973, 1340889772, 591021089923, 260625046992322, 114934898294104873, 50686253523654314872, 22352636009353302099823, 9857512392190471938857422, 4347162960647215744965074773
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 491*a(n-1) - 22099*a(n-2) + 21609*a(n-3).
Conjectures from Colin Barker, Oct 10 2018: (Start)
G.f.: x*(23 - 4071*x + 17248*x^2) / ((1 - x)*(1 - 49*x)*(1 - 441*x)).
a(n) = (2205 + 486*49^n + 125*441^n) / 3528.
(End)
EXAMPLE
Some solutions for n=2:
..0..1..2..1....0..1..1..1....0..1..5..1....0..0..1..2....0..1..2..1
..0..2..1..1....1..5..5..2....2..4..3..1....3..3..0..3....2..1..2..0
CROSSREFS
Column 4 of A233217.
Sequence in context: A045735 A233109 A193430 * A368142 A368145 A090674
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 06 2013
STATUS
approved