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A274729 Number of 4 X n 0..2 arrays with no element equal to any value at offset (-1,-2) (-2,-1) or (-1,0) and new values introduced in order 0..2.

%I A274729 #9 Jan 30 2019 10:55:43
%S A274729 4,48,260,1632,10368,66132,421904,2691884,17175124,109583308,
%T A274729 699179884,4461012792,28462825592,181602806300,1158689573772,
%U A274729 7392845715224,47168947581908,300954422923484,1920194732348424,12251515609312728
%N A274729 Number of 4 X n 0..2 arrays with no element equal to any value at offset (-1,-2) (-2,-1) or (-1,0) and new values introduced in order 0..2.
%H A274729 R. H. Hardin, <a href="/A274729/b274729.txt">Table of n, a(n) for n = 1..210</a>
%F A274729 Empirical: a(n) = 8*a(n-1) - 10*a(n-2) - 4*a(n-3) + 13*a(n-4) - 7*a(n-5) + a(n-6) for n>7.
%F A274729 Empirical g.f.: 4*x*(1 + 4*x - 21*x^2 + 12*x^3 + 13*x^4 - 12*x^5 + 2*x^6) / ((1 - x)*(1 - 7*x + 3*x^2 + 7*x^3 - 6*x^4 + x^5)). - _Colin Barker_, Jan 30 2019
%e A274729 Some solutions for n=4:
%e A274729 ..0..1..0..2. .0..1..2..1. .0..1..2..0. .0..1..0..2. .0..1..0..0
%e A274729 ..1..2..1..0. .1..2..1..2. .2..0..1..2. .2..2..1..0. .1..2..2..2
%e A274729 ..2..1..2..1. .2..1..2..1. .0..1..0..1. .0..1..0..1. .2..1..0..1
%e A274729 ..1..0..1..0. .1..2..1..2. .1..0..1..0. .1..0..1..0. .1..2..1..0
%Y A274729 Row 4 of A274728.
%K A274729 nonn
%O A274729 1,1
%A A274729 _R. H. Hardin_, Jul 03 2016