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A306048
Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 3, 6 or 7 king-move adjacent elements, with upper left element zero.
1
4, 21, 45, 142, 439, 1261, 3826, 11770, 35152, 106027, 323339, 977445, 2953775, 8969080, 27186554, 82305975, 249564286, 756677843, 2292774262, 6949799639, 21069414963, 63860628612, 193568100369, 586780928193, 1778655998433
OFFSET
1,1
COMMENTS
Column 3 of A306053.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +9*a(n-3) -20*a(n-4) -27*a(n-5) +11*a(n-6) +33*a(n-7) +18*a(n-8) -22*a(n-9) -10*a(n-10) for n>12
EXAMPLE
Some solutions for n=5
..0..0..0. .0..0..0. .0..1..1. .0..1..0. .0..1..0. .0..1..1. .0..1..1
..0..1..1. .0..0..0. .1..0..1. .1..0..1. .1..0..1. .1..1..1. .0..0..1
..0..1..0. .0..0..0. .1..0..1. .1..1..1. .1..1..1. .1..1..1. .1..1..1
..0..0..0. .0..1..0. .0..1..1. .1..0..1. .1..0..1. .1..0..0. .1..0..1
..1..0..0. .1..1..0. .0..1..1. .0..1..0. .1..0..0. .1..0..1. .1..0..0
CROSSREFS
Cf. A306053.
Sequence in context: A273405 A273831 A273847 * A266149 A042223 A317225
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 18 2018
STATUS
approved