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A274891
Number of nX4 0..2 arrays with no element equal to any value at offset (0,-1) (-1,-1) or (-2,0) and new values introduced in order 0..2.
1
4, 36, 37, 104, 275, 753, 2049, 5602, 15305, 41866, 114475, 313122, 856462, 2342559, 6407780, 17526908, 47941766, 131135884, 358697083, 981151642, 2683758871, 7340930445, 20079778989, 54924550811, 150236085835, 410943350656
OFFSET
1,1
COMMENTS
Column 4 of A274895.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +8*a(n-2) -28*a(n-4) -9*a(n-5) +55*a(n-6) +16*a(n-7) -70*a(n-8) -9*a(n-9) +56*a(n-10) -28*a(n-12) +a(n-13) +8*a(n-14) -a(n-16) for n>18
EXAMPLE
Some solutions for n=4
..0..1..2..0. .0..1..0..1. .0..1..0..2. .0..1..2..1. .0..1..2..0
..1..2..0..1. .2..1..2..1. .2..1..2..1. .1..2..0..1. .1..2..0..1
..2..0..1..2. .1..0..2..0. .1..0..2..0. .2..0..1..2. .2..0..1..2
..0..1..2..0. .1..2..1..0. .1..0..1..0. .0..1..2..0. .2..0..1..0
CROSSREFS
Cf. A274895.
Sequence in context: A174426 A198642 A327998 * A062182 A308531 A073771
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 10 2016
STATUS
approved