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A270054
Number of nX4 0..4 arrays with some element plus some horizontally or vertically adjacent neighbor totalling four exactly once.
1
240, 99840, 22911300, 4410058320, 779206497960, 130850370606120, 21244602958557060, 3367363526042121600, 524230216822482202860, 80480015854082855624040, 12218158166851049001563640
OFFSET
1,1
COMMENTS
Column 4 of A270058.
LINKS
FORMULA
Empirical: a(n) = 306*a(n-1) -27803*a(n-2) +685150*a(n-3) -6795613*a(n-4) +28270996*a(n-5) -41396356*a(n-6) for n>7
EXAMPLE
Some solutions for n=2
..2..4..2..1. .3..2..1..0. .1..3..4..1. .2..0..0..3. .1..2..3..0
..4..4..0..0. .4..3..2..2. .0..2..1..1. .0..3..2..2. .3..4..3..3
CROSSREFS
Cf. A270058.
Sequence in context: A001943 A052263 A218514 * A213696 A275459 A377220
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 09 2016
STATUS
approved