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A268805 Number of nX4 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two not more than once.

%I A268805 #4 Feb 13 2016 18:20:33
%S A268805 60,290,1202,5848,28452,135912,640926,2990786,13835892,63544542,
%T A268805 290056316,1317009868,5952527788,26795651036,120193389832,
%U A268805 537427198324,2396207992178,10656560102448,47282655935580,209348341875062
%N A268805 Number of nX4 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two not more than once.
%C A268805 Column 4 of A268809.
%H A268805 R. H. Hardin, <a href="/A268805/b268805.txt">Table of n, a(n) for n = 1..210</a>
%F A268805 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 A268805 Some solutions for n=4
%e A268805 ..2..2..2..2. .2..2..2..1. .1..2..1..2. .2..2..1..2. .0..2..2..2
%e A268805 ..2..1..2..1. .1..2..1..2. .1..2..2..2. .1..2..1..2. .1..2..1..2
%e A268805 ..1..2..2..2. .2..2..2..2. .2..2..2..1. .2..2..2..2. .2..2..2..2
%e A268805 ..2..2..1..2. .1..2..2..1. .1..2..2..2. .1..2..1..2. .1..2..2..2
%Y A268805 Cf. A268809.
%K A268805 nonn
%O A268805 1,1
%A A268805 _R. H. Hardin_, Feb 13 2016