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A303713
Number of n X n 0..1 arrays with every element unequal to 0, 1 or 5 king-move adjacent elements, with upper left element zero.
1
1, 1, 5, 17, 81, 343, 1592, 7551, 34546, 158402, 734321, 3389249, 15610239, 72045856, 332515175, 1533661362, 7075164898, 32644176977, 150600651761, 694773927239, 3205360278072, 14787893322847, 68223139662242, 314745564736962
OFFSET
1,3
COMMENTS
Diagonal of A303719.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +2*a(n-2) +28*a(n-3) -2*a(n-4) -42*a(n-5) -56*a(n-6) +50*a(n-7) -44*a(n-8) +30*a(n-9) -44*a(n-10) +2*a(n-11) +2*a(n-12) -a(n-14) +a(n-15) for n>18.
EXAMPLE
Some solutions for n=5
..0..0..0..0..0. .0..0..0..1..0. .0..0..0..1..0. .0..0..0..0..0
..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0
..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..1
..1..0..0..0..0. .1..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0
..0..0..0..1..0. .0..0..0..0..0. .0..0..1..0..0. .0..0..0..0..0
CROSSREFS
Cf. A303719.
Sequence in context: A149750 A179605 A149751 * A188231 A023253 A149752
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 29 2018
STATUS
approved