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A208430 Number of nX4 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 A208430 #7 Jun 02 2025 07:44:39
%S A208430 14,216,339,1292,6416,32813,169899,885540,4617014,24074947,125562891,
%T A208430 654899967,3415879346,17817085346,92933586111,484741782266,
%U A208430 2528419901343,13188283797088,68790359883448,358812044639010,1871571851010931
%N A208430 Number of nX4 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 A208430 Column 4 of A208434
%H A208430 R. H. Hardin, <a href="/A208430/b208430.txt">Table of n, a(n) for n = 1..210</a>
%F A208430 Empirical: a(n) = 7*a(n-1) -6*a(n-2) -11*a(n-3) -36*a(n-4) -39*a(n-5) +276*a(n-6) +153*a(n-7) -71*a(n-8) -518*a(n-9) -1682*a(n-10) +1463*a(n-11) +2788*a(n-12) -2181*a(n-13) -273*a(n-14) +1238*a(n-15) -2067*a(n-16) +301*a(n-17) +1071*a(n-18) -635*a(n-19) +133*a(n-20) +286*a(n-21) -194*a(n-22) -38*a(n-23) +80*a(n-24) -46*a(n-25) -14*a(n-26) +20*a(n-27) -4*a(n-28) for n>34
%e A208430 Some solutions for n=4
%e A208430 ..0..0..0..0....0..0..0..1....0..0..0..1....0..0..1..2....0..0..0..1
%e A208430 ..1..2..2..2....1..2..1..1....1..2..1..1....0..1..1..1....1..2..1..1
%e A208430 ..1..1..2..1....2..2..2..1....2..2..2..1....2..2..1..0....2..2..2..1
%e A208430 ..1..0..0..0....1..0..0..0....0..2..0..0....0..2..0..0....1..2..0..0
%K A208430 nonn
%O A208430 1,1
%A A208430 _R. H. Hardin_ Feb 26 2012