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A269147
Number of nX3 0..3 arrays with some element plus some horizontally, antidiagonally or vertically adjacent neighbor totalling three exactly once.
1
24, 768, 13904, 220968, 3277728, 46576336, 642676704, 8680278136, 115349343264, 1513379596864, 19651887694240, 253030595298696, 3234828051983328, 41105657832397744, 519625334069189984, 6539008095907322520
OFFSET
1,1
COMMENTS
Column 3 of A269152.
LINKS
FORMULA
Empirical: a(n) = 26*a(n-1) -199*a(n-2) +408*a(n-3) -463*a(n-4) +322*a(n-5) -141*a(n-6) +36*a(n-7) -4*a(n-8) for n>9
EXAMPLE
Some solutions for n=3
..0..2..3. .0..1..1. .3..1..0. .2..2..3. .0..0..3. .0..0..1. .3..2..2
..0..0..2. .3..1..0. .1..0..1. .2..2..3. .0..2..2. .1..0..0. .3..3..3
..1..0..2. .1..0..2. .0..0..2. .0..2..1. .2..3..2. .0..1..3. .1..2..2
CROSSREFS
Cf. A269152.
Sequence in context: A283873 A359480 A361661 * A269209 A270252 A275635
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 20 2016
STATUS
approved