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A268794 Number of nX4 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two exactly once. 1

%I #4 Feb 13 2016 13:42:32

%S 36,234,950,4800,23994,117062,561116,2652936,12405748,57490444,

%T 264428454,1208522850,5493284922,24851601802,111963916212,

%U 502590509990,2248738675490,10032298715910,44640056867750,198161794087570

%N Number of nX4 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two exactly once.

%C Column 4 of A268798.

%H R. H. Hardin, <a href="/A268794/b268794.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) +19*a(n-2) +10*a(n-3) -122*a(n-4) -320*a(n-5) -295*a(n-6) +8*a(n-7) +176*a(n-8) +20*a(n-9) -98*a(n-10) -6*a(n-11) +43*a(n-12) -6*a(n-13) -11*a(n-14) +6*a(n-15) -a(n-16) for n>19

%e Some solutions for n=4

%e ..0..1..2..1. .2..2..1..2. .0..0..0..0. .1..2..2..2. .2..2..2..2

%e ..2..2..2..2. .2..2..2..1. .0..1..0..1. .1..2..2..2. .1..2..2..1

%e ..1..2..1..2. .1..2..2..2. .0..0..1..0. .2..2..2..1. .2..2..2..2

%e ..2..2..2..1. .1..2..2..1. .1..0..0..0. .2..2..2..2. .1..1..2..2

%Y Cf. A268798.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 13 2016

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Last modified June 6 10:03 EDT 2024. Contains 373127 sequences. (Running on oeis4.)