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A317858 Number of nX3 0..1 arrays with every element unequal to 1, 2 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 1

%I #4 Aug 09 2018 09:43:58

%S 1,6,4,19,32,72,164,331,790,1700,3879,8689,19763,44787,101708,232136,

%T 528496,1206975,2755982,6298876,14399412,32932776,75341117,172383450,

%U 394513860,902958422,2066919648,4731632878,10832452949,24800620478

%N Number of nX3 0..1 arrays with every element unequal to 1, 2 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 3 of A317863.

%H R. H. Hardin, <a href="/A317858/b317858.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5*a(n-2) +8*a(n-3) -2*a(n-4) -26*a(n-5) -32*a(n-6) +6*a(n-7) +40*a(n-8) +32*a(n-9) -3*a(n-10) -16*a(n-11) +17*a(n-12) +6*a(n-13) -20*a(n-14) -6*a(n-15) +19*a(n-16) +14*a(n-17) -14*a(n-19) -5*a(n-20) +2*a(n-21) -10*a(n-22) +3*a(n-24) +a(n-26) for n>32

%e Some solutions for n=5

%e ..0..1..0. .0..1..1. .0..1..0. .0..0..0. .0..1..1. .0..1..0. .0..1..0

%e ..0..0..1. .0..1..0. .0..0..0. .1..1..0. .1..1..0. .1..1..0. .1..1..0

%e ..1..1..1. .0..0..0. .1..0..1. .1..0..1. .1..1..1. .0..0..0. .1..1..0

%e ..1..0..0. .1..0..1. .0..0..0. .0..1..1. .0..1..1. .0..1..1. .0..0..0

%e ..0..1..0. .0..0..0. .0..1..0. .0..0..0. .1..0..1. .1..0..1. .0..1..0

%Y Cf. A317863.

%K nonn

%O 1,2

%A _R. H. Hardin_, Aug 09 2018

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Last modified March 28 04:13 EDT 2024. Contains 371235 sequences. (Running on oeis4.)