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A231840 Number of 2Xn 0..3 arrays with no element less than a strict majority of its horizontal and antidiagonal neighbors.

%I A231840 #6 Jul 23 2025 06:43:28
%S A231840 16,50,188,760,3309,14666,64607,283479,1243280,5452114,23905237,
%T A231840 104828007,459770373,2016638186,8845269109,38796696140,170170211095,
%U A231840 746407664707,3273942709889,14360456936977,62989372397071
%N A231840 Number of 2Xn 0..3 arrays with no element less than a strict majority of its horizontal and antidiagonal neighbors.
%C A231840 Row 2 of A231839
%H A231840 R. H. Hardin, <a href="/A231840/b231840.txt">Table of n, a(n) for n = 1..210</a>
%F A231840 Empirical: a(n) = 16*a(n-1) -120*a(n-2) +594*a(n-3) -2230*a(n-4) +6728*a(n-5) -16873*a(n-6) +35897*a(n-7) -65873*a(n-8) +105776*a(n-9) -149668*a(n-10) +188619*a(n-11) -211559*a(n-12) +213408*a(n-13) -191583*a(n-14) +154654*a(n-15) -110323*a(n-16) +68713*a(n-17) -37978*a(n-18) +15027*a(n-19) -6519*a(n-20) -1220*a(n-21) -499*a(n-22) -1885*a(n-23) -410*a(n-24) -615*a(n-25) -257*a(n-26) -118*a(n-27) -60*a(n-28) -15*a(n-29) -5*a(n-30) -a(n-31) for n>32
%e A231840 Some solutions for n=5
%e A231840 ..1..1..1..0..0....3..3..3..3..2....2..1..1..2..1....3..0..0..0..0
%e A231840 ..2..1..0..0..1....2..2..2..2..3....1..1..1..1..2....0..1..1..1..2
%K A231840 nonn
%O A231840 1,1
%A A231840 _R. H. Hardin_, Nov 14 2013