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A180754 Half the number of nX5 binary arrays with each element equal to at least two neighbors.

%I A180754 #5 Jul 22 2025 08:28:27
%S A180754 0,3,3,21,86,410,1874,8840,41755,197883,936625,4434387,20996674,
%T A180754 99434998,470911050,2230166446,10561720749,50018822099,236882697591,
%U A180754 1121846953883,5312927519916,25161362888858,119161085234850,564332106834338
%N A180754 Half the number of nX5 binary arrays with each element equal to at least two neighbors.
%C A180754 Column 5 of A180760
%H A180754 R. H. Hardin, <a href="/A180754/b180754.txt">Table of n, a(n) for n=1..99</a>
%F A180754 Empirical: a(n) = 9*a(n-1) - 26*a(n-2) + 24*a(n-3) + 47*a(n-4) - 157*a(n-5) - 43*a(n-6) + 641*a(n-7) - 643*a(n-8) - 952*a(n-9) + 3460*a(n-10) - 2021*a(n-11) - 2111*a(n-12) + 2715*a(n-13) - 1249*a(n-14) - 4657*a(n-15) - 1514*a(n-16) + 1961*a(n-17) - 1230*a(n-18) + 6713*a(n-19) + 8832*a(n-20) + 10212*a(n-21) + 1971*a(n-22) - 6552*a(n-23) - 2819*a(n-24) - 2898*a(n-25) - 973*a(n-26) + 302*a(n-27) + 433*a(n-28) + 286*a(n-29)
%K A180754 nonn
%O A180754 1,2
%A A180754 _R. H. Hardin_ Sep 20 2010