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%I #4 Oct 30 2013 20:31:06
%S 0,6,10,62,176,734,3034,12962,55806,241462,1047244,4548392,19770622,
%T 85983476,374071534,1627718734,7083554700,30828250368,134171670508,
%U 583957263660,2541594468334,11062020222648,48146469919922
%N Number of nX4 0..3 arrays x(i,j) with each element horizontally, vertically or antidiagonally next to at least one element with value (x(i,j)+1) mod 4 and at least one element with value (x(i,j)-1) mod 4, no adjacent elements equal, and upper left element zero
%C Column 4 of A230831
%H R. H. Hardin, <a href="/A230827/b230827.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 20*a(n-1) -174*a(n-2) +856*a(n-3) -2543*a(n-4) +4242*a(n-5) -1758*a(n-6) -8383*a(n-7) +18429*a(n-8) -9998*a(n-9) -19479*a(n-10) +35858*a(n-11) -3796*a(n-12) -44630*a(n-13) +26155*a(n-14) +46885*a(n-15) -36285*a(n-16) -52603*a(n-17) +27731*a(n-18) +62520*a(n-19) -8480*a(n-20) -68927*a(n-21) +7432*a(n-22) +63362*a(n-23) -4203*a(n-24) -57711*a(n-25) -41467*a(n-26) +16827*a(n-27) +61539*a(n-28) +68672*a(n-29) +13282*a(n-30) -105380*a(n-31) -115207*a(n-32) +42704*a(n-33) +133454*a(n-34) +42704*a(n-35) -68204*a(n-36) -61800*a(n-37) +6457*a(n-38) +32367*a(n-39) +12804*a(n-40) -4313*a(n-41) -5391*a(n-42) -1966*a(n-43) -339*a(n-44) -26*a(n-45) -a(n-46) for n>51
%e Some solutions for n=4
%e ..0..1..0..1....0..3..2..3....0..1..3..2....0..1..2..0....0..1..2..0
%e ..3..2..3..2....1..0..1..0....3..2..0..1....3..0..3..1....3..0..3..1
%e ..0..1..0..1....2..3..2..3....0..1..3..2....2..1..2..3....2..1..2..3
%e ..3..2..3..2....1..0..1..0....3..2..0..1....0..3..1..0....3..0..1..0
%K nonn
%O 1,2
%A _R. H. Hardin_, Oct 30 2013
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