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A230660 Number of nX7 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j).

%I A230660 #6 Jun 02 2025 08:44:35
%S A230660 0,63,1155,11745,477279,3951657,169006665,1374288243,59075291211,
%T A230660 479621050353,20625942501183,167435671598913,7200781142959245,
%U A230660 58453268091967479,2513864130034802115,20406595554618417837
%N A230660 Number of nX7 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j).
%C A230660 Column 7 of A230661
%H A230660 R. H. Hardin, <a href="/A230660/b230660.txt">Table of n, a(n) for n = 1..210</a>
%F A230660 Empirical: a(n) = 390*a(n-2) -14687*a(n-4) +146138*a(n-6) -823339*a(n-8) -2774563*a(n-10) +26807114*a(n-12) -60400888*a(n-14) +106367378*a(n-16) -35490451*a(n-18) -7548040169*a(n-20) +1542760687*a(n-22) +7961883650*a(n-24) +3473400076*a(n-26) +61902164677*a(n-28) +25546220017*a(n-30) +84369583536*a(n-32) +75320917456*a(n-34) +42723111397*a(n-36) -5387877662*a(n-38) +926204972*a(n-40) -121037200*a(n-42) +10124352*a(n-44) +414720*a(n-46) for n>47
%e A230660 Some solutions for n=5
%e A230660 ..x..0..x..1..x..2..x....x..0..x..1..x..1..x....x..0..x..0..x..0..x
%e A230660 ..2..x..0..x..1..x..0....0..x..2..x..1..x..1....0..x..2..x..2..x..0
%e A230660 ..x..1..x..2..x..2..x....x..2..x..1..x..0..x....x..2..x..2..x..2..x
%e A230660 ..0..x..1..x..2..x..0....0..x..1..x..2..x..1....2..x..0..x..2..x..1
%e A230660 ..x..2..x..1..x..0..x....x..2..x..0..x..1..x....x..0..x..0..x..1..x
%K A230660 nonn
%O A230660 1,2
%A A230660 _R. H. Hardin_, Oct 27 2013