%I #6 Jun 26 2022 04:21:27

%S 0,1,34,395,3996,37869,338397,2903399,24188526,196906027,1573282195,

%T 12379155797,96158433169,738796369876,5622865097337,42443605420288,

%U 318066721949699,2368270143804417,17532717135478046,129129170044433714

%N Number of n X 3 0..1 arrays with no 1 equal to more than two of its horizontal and vertical neighbors, with the exception of exactly two elements.

%C Column 3 of A283232.

%H R. H. Hardin, <a href="/A283227/b283227.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 15*a(n-1) -54*a(n-2) -10*a(n-3) -318*a(n-4) +1056*a(n-5) +3892*a(n-6) +15081*a(n-7) +28818*a(n-8) +47074*a(n-9) +42561*a(n-10) +16083*a(n-11) -40047*a(n-12) -76149*a(n-13) -66630*a(n-14) -5493*a(n-15) +53052*a(n-16) +53256*a(n-17) +9505*a(n-18) -26049*a(n-19) -17790*a(n-20) +3537*a(n-21) +5733*a(n-22) +369*a(n-23) -753*a(n-24) -126*a(n-25) +36*a(n-26) +8*a(n-27).

%e Some solutions for n=4

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

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

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

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

%Y Cf. A283232.

%K nonn

%O 1,3

%A _R. H. Hardin_, Mar 03 2017