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Number of n X 3 0..3 arrays with no more than floor(n X 3/2) elements unequal to at least one horizontal, vertical or antidiagonal neighbor, with new values introduced in row major 0..3 order.
1

%I #6 Dec 30 2023 21:55:23

%S 1,3,5,65,181,3545,11421,243955,829319,17592855,61952605,1284213397,

%T 4662579053,94370045311,351914237859,6970771357553,26611889407629,

%U 517258600443449,2015559262618275,38540189430369807,152866542948213595

%N Number of n X 3 0..3 arrays with no more than floor(n X 3/2) elements unequal to at least one horizontal, vertical or antidiagonal neighbor, with new values introduced in row major 0..3 order.

%C Column 3 of A222616.

%H R. H. Hardin, <a href="/A222611/b222611.txt">Table of n, a(n) for n = 1..204</a>

%e All solutions for n=3

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

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

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

%Y Cf. A222616.

%K nonn

%O 1,2

%A _R. H. Hardin_, Feb 26 2013