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A237569 Number of (n+1)X(1+1) 0..3 arrays with the upper median minus the lower median of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one.

%I A237569 #7 Jul 23 2025 10:18:47
%S A237569 256,1876,13924,103264,769680,5705156,42501300,315065200,2347267424,
%T A237569 17400203636,129631996580,960959725312,7159191300272,53070925060004,
%U A237569 395380448791316,2930946979641872,21835672557183872,161867373265982548
%N A237569 Number of (n+1)X(1+1) 0..3 arrays with the upper median minus the lower median of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one.
%C A237569 Column 1 of A237574
%H A237569 R. H. Hardin, <a href="/A237569/b237569.txt">Table of n, a(n) for n = 1..210</a>
%F A237569 Empirical: a(n) = 23*a(n-2) +1473*a(n-4) +15833*a(n-6) +60176*a(n-8) +65344*a(n-10) -70656*a(n-12) -139264*a(n-14) for n>15
%e A237569 Some solutions for n=4
%e A237569 ..2..3....1..1....2..1....1..1....3..2....2..2....2..2....3..2....3..3....0..2
%e A237569 ..1..1....1..3....3..2....0..3....1..1....2..2....1..1....1..1....0..1....2..1
%e A237569 ..3..3....1..2....1..1....3..2....3..0....1..1....1..3....1..0....1..0....3..2
%e A237569 ..2..0....0..1....1..0....2..0....1..0....3..1....0..0....0..3....0..0....0..1
%e A237569 ..2..2....3..0....2..3....1..0....3..3....3..2....3..0....3..3....1..3....0..0
%K A237569 nonn
%O A237569 1,1
%A A237569 _R. H. Hardin_, Feb 09 2014