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A269279
Number of 4Xn 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three exactly once.
1
0, 20412, 1365336, 74853576, 3719884392, 174924572760, 7934992835112, 350946381867480, 15232155757251048, 651580499598523992, 27551808205246504872, 1154085846201751972824, 47965168186749101620584
OFFSET
1,2
COMMENTS
Row 4 of A269276.
LINKS
FORMULA
Empirical: a(n) = 96*a(n-1) -3108*a(n-2) +40720*a(n-3) -265326*a(n-4) +931200*a(n-5) -1766452*a(n-6) +1678992*a(n-7) -622521*a(n-8) for n>12
EXAMPLE
Some solutions for n=2
..0..3. .2..0. .1..3. .1..3. .0..2. .0..2. .0..1. .0..2. .0..1. .1..3
..3..3. .0..0. .0..0. .3..1. .3..3. .3..2. .3..2. .2..3. .3..1. .2..2
..2..2. .1..3. .2..2. .2..2. .0..2. .1..0. .0..1. .3..2. .3..0. .1..3
..0..2. .1..2. .0..1. .3..2. .2..3. .0..2. .1..2. .1..3. .0..0. .1..1
CROSSREFS
Cf. A269276.
Sequence in context: A182294 A103912 A256104 * A234552 A223466 A281658
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 21 2016
STATUS
approved