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A208431 Number of nX5 0..2 arrays with new values 0..2 introduced in row major order and no element equal to any knight-move neighbor (colorings ignoring permutations of colors).

%I A208431 #7 Jun 02 2025 07:44:46
%S A208431 41,864,1123,6416,50507,365195,2623167,19281232,141789341,1037399092,
%T A208431 7598755762,55697097923,408217653315,2991035581961,21919561041622,
%U A208431 160626736704557,1177121839740932,8625904039667696,63212673380523055
%N A208431 Number of nX5 0..2 arrays with new values 0..2 introduced in row major order and no element equal to any knight-move neighbor (colorings ignoring permutations of colors).
%C A208431 Column 5 of A208434
%H A208431 R. H. Hardin, <a href="/A208431/b208431.txt">Table of n, a(n) for n = 1..210</a>
%F A208431 Empirical: a(n) = 8*a(n-1) +17*a(n-2) -201*a(n-3) +448*a(n-4) -1627*a(n-5) +1693*a(n-6) +22432*a(n-7) -60066*a(n-8) +45696*a(n-9) +32264*a(n-10) -697137*a(n-11) +1671442*a(n-12) -378862*a(n-13) -2203329*a(n-14) +8634970*a(n-15) -17270425*a(n-16) +2222078*a(n-17) +16804877*a(n-18) -40251356*a(n-19) +104103432*a(n-20) -64341121*a(n-21) -37339570*a(n-22) +110797160*a(n-23) -350390806*a(n-24) +352758000*a(n-25) -4026468*a(n-26) -221511112*a(n-27) +581590756*a(n-28) -647331256*a(n-29) +39507416*a(n-30) +335397720*a(n-31) -417266928*a(n-32) +342507344*a(n-33) +68614176*a(n-34) -240816608*a(n-35) +52389024*a(n-36) +43953792*a(n-37) -21497088*a(n-38) +4329216*a(n-39) +746496*a(n-40) -746496*a(n-41) for n>45
%e A208431 Some solutions for n=4
%e A208431 ..0..0..1..1..1....0..0..0..0..1....0..1..0..2..1....0..1..2..1..0
%e A208431 ..0..0..2..1..0....2..1..2..2..2....2..0..2..2..1....0..2..1..2..0
%e A208431 ..1..2..2..2..0....1..1..1..2..1....0..1..0..2..0....2..1..2..1..0
%e A208431 ..1..1..2..1..0....2..0..0..0..0....1..0..1..0..1....1..2..1..2..1
%K A208431 nonn
%O A208431 1,1
%A A208431 _R. H. Hardin_ Feb 26 2012