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A241115 Number of nX3 0..3 arrays with no element equal to exactly three horizontal or vertical neighbors, with new values 0..3 introduced in row major order.

%I A241115 #7 Jul 23 2025 11:10:24
%S A241115 5,178,9918,587555,35000157,2085879115,124315318217,7409032909403,
%T A241115 441568937568818,26316947602316573,1568456640467509976,
%U A241115 93478023005207665450,5571171404819117025366,332034737407500793137773
%N A241115 Number of nX3 0..3 arrays with no element equal to exactly three horizontal or vertical neighbors, with new values 0..3 introduced in row major order.
%C A241115 Column 3 of A241119
%H A241115 R. H. Hardin, <a href="/A241115/b241115.txt">Table of n, a(n) for n = 1..210</a>
%F A241115 Empirical: a(n) = 60*a(n-1) -7*a(n-2) -972*a(n-3) -2112*a(n-4) -2660*a(n-5) +12008*a(n-6) +48742*a(n-7) +35629*a(n-8) -20302*a(n-9) -27711*a(n-10) -65688*a(n-11) -146133*a(n-12) -130104*a(n-13) -24426*a(n-14) +56268*a(n-15) +56538*a(n-16) +13284*a(n-17) -5103*a(n-18) -5346*a(n-19) -1458*a(n-20) for n>21
%e A241115 Some solutions for n=3
%e A241115 ..0..1..1....0..1..2....0..0..1....0..0..1....0..1..0....0..1..2....0..1..2
%e A241115 ..2..2..2....0..0..2....2..2..2....1..2..2....2..3..2....2..1..0....0..1..0
%e A241115 ..3..1..3....1..2..0....0..3..0....2..3..0....0..0..3....2..3..3....1..0..1
%K A241115 nonn
%O A241115 1,1
%A A241115 _R. H. Hardin_, Apr 16 2014