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R. H. Hardin, <a href="/A316513/b316513.txt">Table of n, a(n) for n = 1..210</a>
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Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 3, 7 or 8 king-move adjacent elements, with upper left element zero.
4, 21, 28, 75, 174, 414, 1002, 2398, 5743, 13785, 33053, 79248, 190054, 455751, 1092871, 2620730, 6284531, 15070301, 36138673, 86660727, 207812777, 498336020, 1195012127, 2865644552, 6871828916, 16478677644, 39515945239, 94759419700
1,1
Column 3 of A316518.
Empirical: a(n) = a(n-1) +2*a(n-2) +3*a(n-3) +a(n-4) -a(n-5) for n>8
Some solutions for n=5
..0..0..1. .0..1..0. .0..1..0. .0..0..1. .0..0..1. .0..0..0. .0..0..1
..0..1..0. .1..1..1. .1..1..1. .0..0..0. .0..0..0. .1..1..1. .0..1..0
..0..0..0. .1..0..1. .1..1..1. .0..1..0. .0..1..0. .1..1..1. .0..0..0
..0..0..0. .1..1..1. .1..1..1. .0..0..0. .1..0..0. .1..1..1. .0..1..0
..1..0..1. .0..1..1. .1..1..1. .1..0..1. .1..0..0. .0..0..0. .0..0..0
Cf. A316518.
allocated
nonn
R. H. Hardin, Jul 05 2018
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