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A208171 Number of nX4 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors.

%I A208171 #7 Jul 22 2025 21:13:30
%S A208171 15,2277,473928,99752346,21002874867,4422202024212,931104734002155,
%T A208171 196046229442844736,41277981610623482478,8691173355900504027213,
%U A208171 1829946411015625966726620,385299398603702723040648261
%N A208171 Number of nX4 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors.
%C A208171 Column 4 of A208175
%H A208171 R. H. Hardin, <a href="/A208171/b208171.txt">Table of n, a(n) for n = 1..210</a>
%F A208171 Empirical: a(n) = 226*a(n-1) -3345*a(n-2) +19752*a(n-3) -60897*a(n-4) +108504*a(n-5) -114399*a(n-6) +68040*a(n-7) -18225*a(n-8) for n>9
%e A208171 Some solutions for n=4
%e A208171 ..0..0..0..1....0..1..0..0....0..0..0..1....0..0..0..0....0..0..1..0
%e A208171 ..1..1..0..0....2..0..3..0....0..1..1..0....0..1..1..2....2..0..1..2
%e A208171 ..2..3..3..0....2..0..3..1....0..1..2..3....1..0..1..3....1..3..0..0
%e A208171 ..0..2..1..3....1..2..0..2....3..0..3..1....1..3..3..1....1..3..2..2
%K A208171 nonn
%O A208171 1,1
%A A208171 _R. H. Hardin_ Feb 24 2012