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A222880 Number of 3Xn 0..3 arrays with no more than floor(3Xn/2) elements equal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order.

%I A222880 #6 Jul 23 2025 03:12:12
%S A222880 5,131,6282,409775,19707855,1340197778,66248732403,4552388850792,
%T A222880 228017377191609,15767959380970741,797585318305106129,
%U A222880 55339415802965980962,2819443488435447752525,196019624814751455019691
%N A222880 Number of 3Xn 0..3 arrays with no more than floor(3Xn/2) elements equal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order.
%C A222880 Row 3 of A222878
%H A222880 R. H. Hardin, <a href="/A222880/b222880.txt">Table of n, a(n) for n = 1..22</a>
%e A222880 Some solutions for n=3
%e A222880 ..0..1..0....0..1..2....0..1..1....0..1..2....0..1..2....0..0..1....0..1..0
%e A222880 ..2..0..1....1..3..2....2..1..3....3..3..0....3..1..0....0..2..3....2..2..2
%e A222880 ..2..0..3....2..1..1....2..0..1....1..1..3....1..1..2....3..2..3....3..2..3
%K A222880 nonn
%O A222880 1,1
%A A222880 _R. H. Hardin_ Mar 08 2013