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A230736 Number of (n+3)X(2+3) 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero.

%I A230736 #6 Jul 23 2025 05:59:07
%S A230736 8,66,244,2016,6576,54138,173428,1427040,4558536,37506738,119758148,
%T A230736 985334832,3145930352,25883741898,82639468964,679931791152,
%U A230736 2170826159272,17860880147874,57024624645332,469180811419968,1497958570841456
%N A230736 Number of (n+3)X(2+3) 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero.
%C A230736 Column 2 of A230739
%H A230736 R. H. Hardin, <a href="/A230736/b230736.txt">Table of n, a(n) for n = 1..210</a>
%F A230736 Empirical: a(n) = 31*a(n-2) -126*a(n-4) +42*a(n-6) +79*a(n-8) -a(n-10) +8*a(n-12)
%e A230736 Some solutions for n=3
%e A230736 ..x..0..x..0..x....x..0..x..1..x....x..0..x..2..x....x..0..x..0..x
%e A230736 ..2..x..1..x..1....1..x..2..x..0....2..x..1..x..0....2..x..1..x..2
%e A230736 ..x..1..x..2..x....x..2..x..1..x....x..1..x..1..x....x..2..x..2..x
%e A230736 ..0..x..0..x..1....1..x..0..x..0....0..x..2..x..0....0..x..0..x..1
%e A230736 ..x..0..x..2..x....x..2..x..2..x....x..0..x..2..x....x..1..x..0..x
%e A230736 ..2..x..1..x..1....1..x..1..x..1....2..x..1..x..1....0..x..2..x..2
%K A230736 nonn
%O A230736 1,1
%A A230736 _R. H. Hardin_, Oct 28 2013