%I #8 Jan 31 2019 09:22:32
%S 3,18,46,137,401,1152,3336,9720,28277,82174,238829,694135,2017380,
%T 5863430,17042197,49533046,143966504,418434888,1216170841,3534771986,
%U 10273734201,29860375290,86788495974,252248762928,733155217213
%N Number of 3 X n 0..2 arrays with no element equal to any value at offset (0,-1) (-1,-2) or (-2,0) and new values introduced in order 0..2.
%H R. H. Hardin, <a href="/A275038/b275038.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) - 2*a(n-2) + 4*a(n-3) + a(n-4) + 3*a(n-5) + 8*a(n-6) + a(n-7) - 3*a(n-8) - a(n-9) for n>10.
%F Empirical g.f.: x*(3 + 9*x - 2*x^2 + 23*x^3 + 7*x^4 + 12*x^5 + 10*x^6 - 10*x^7 - 8*x^8 - x^9) / (1 - 3*x + 2*x^2 - 4*x^3 - x^4 - 3*x^5 - 8*x^6 - x^7 + 3*x^8 + x^9). - _Colin Barker_, Jan 31 2019
%e Some solutions for n=4:
%e ..0..1..2..1. .0..1..0..1. .0..1..0..1. .0..1..0..2. .0..1..2..0
%e ..2..1..2..0. .0..1..2..0. .0..2..1..0. .0..1..2..0. .0..1..2..0
%e ..2..0..1..0. .1..0..2..0. .1..0..1..0. .1..0..1..0. .1..0..1..2
%Y Row 3 of A275037.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jul 14 2016