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A304467
Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 3 or 6 king-move adjacent elements, with upper left element zero.
1
4, 21, 41, 117, 316, 810, 2208, 6012, 15837, 42579, 115618, 309144, 829935, 2246106, 6045980, 16264045, 43945153, 118607081, 319754491, 863718047, 2333646132, 6300949455, 17025299379, 46023642233, 124382811126, 336236258224
OFFSET
1,1
COMMENTS
Column 3 of A304472.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +8*a(n-3) -21*a(n-4) -26*a(n-5) +10*a(n-6) +31*a(n-7) +20*a(n-8) -20*a(n-9) -10*a(n-10) for n>12
EXAMPLE
Some solutions for n=5
..0..1..0. .0..0..1. .0..0..0. .0..0..1. .0..1..0. .0..1..1. .0..1..1
..1..1..1. .0..0..0. .0..0..0. .0..1..1. .0..1..1. .0..1..1. .0..1..0
..1..1..0. .1..1..0. .0..0..0. .1..1..1. .0..0..0. .0..1..1. .0..0..0
..1..0..0. .1..0..0. .0..0..0. .1..1..1. .0..0..0. .1..0..1. .1..0..0
..1..1..1. .0..0..0. .0..0..0. .0..1..1. .1..0..1. .0..1..1. .1..1..0
CROSSREFS
Cf. A304472.
Sequence in context: A110737 A273417 A273443 * A316284 A349807 A273405
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 13 2018
STATUS
approved