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A268804
Number of nX3 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two not more than once.
1
24, 104, 332, 1202, 4158, 14308, 48460, 162722, 541744, 1791504, 5889586, 19264864, 62738690, 203528858, 658003018, 2120809106, 6816832928, 21856821554, 69922091542, 223229394256, 711333766468, 2262803472594, 7186710244256
OFFSET
1,1
COMMENTS
Column 3 of A268809.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) +9*a(n-2) -2*a(n-3) -33*a(n-4) -42*a(n-5) -14*a(n-6) +10*a(n-7) +8*a(n-8) -a(n-10) for n>12
EXAMPLE
Some solutions for n=4
..0..1..2. .0..1..1. .2..2..1. .1..2..2. .1..0..0. .2..0..0. .2..2..2
..0..0..1. .0..0..0. .1..2..2. .2..2..1. .0..1..0. .1..0..0. .2..1..1
..1..0..0. .0..0..0. .2..1..2. .1..2..2. .0..0..1. .0..1..0. .2..2..2
..0..0..0. .1..0..1. .1..2..2. .2..1..1. .0..1..2. .0..0..0. .2..2..1
CROSSREFS
Cf. A268809.
Sequence in context: A182675 A100155 A304415 * A186932 A275506 A185743
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 13 2016
STATUS
approved