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A280854 Number of n X 3 0..2 arrays with no element equal to more than one of its king-move neighbors and with new values introduced in order 0 sequentially upwards.

%I A280854 #7 Feb 14 2019 10:07:43
%S A280854 4,29,46,96,256,678,1698,4358,11218,28650,73354,188066,481554,1233194,
%T A280854 3159018,8091050,20722730,53077762,135947682,348198514,891836994,
%U A280854 2284251018,5850611770,14985083066,38381073050,98304843826,251786685106
%N A280854 Number of n X 3 0..2 arrays with no element equal to more than one of its king-move neighbors and with new values introduced in order 0 sequentially upwards.
%H A280854 R. H. Hardin, <a href="/A280854/b280854.txt">Table of n, a(n) for n = 1..210</a>
%F A280854 Empirical: a(n) = 2*a(n-1) + 4*a(n-3) - a(n-4) + 2*a(n-6) - 2*a(n-7) for n>9.
%F A280854 Empirical g.f.: x*(4 + 21*x - 12*x^2 - 12*x^3 - 48*x^4 + 11*x^5 - 4*x^6 - 16*x^7 + 12*x^8) / (1 - 2*x - 4*x^3 + x^4 - 2*x^6 + 2*x^7). - _Colin Barker_, Feb 14 2019
%e A280854 Some solutions for n=4:
%e A280854 ..0..0..1. .0..1..1. .0..0..1. .0..1..0. .0..1..2. .0..1..0. .0..0..1
%e A280854 ..1..2..1. .0..2..2. .1..2..2. .2..2..1. .2..1..0. .2..1..2. .2..1..2
%e A280854 ..0..2..0. .1..1..0. .0..1..0. .1..0..0. .2..0..2. .2..0..2. .2..0..0
%e A280854 ..1..1..0. .0..2..2. .0..2..2. .1..2..2. .1..1..2. .1..1..0. .1..1..2
%Y A280854 Column 3 of A280859.
%K A280854 nonn
%O A280854 1,1
%A A280854 _R. H. Hardin_, Jan 09 2017