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%I #4 Nov 01 2013 07:06:09
%S 0,26,152,802,4308,23614,130178,718750,3970738,21941252,121252356,
%T 670093980,3703301746,20466628218,113111135842,625122784014,
%U 3454822416978,19093535079990,105522984179168,583187006699888
%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, no adjacent elements equal, and upper left element zero
%C Column 4 of A230910
%H R. H. Hardin, <a href="/A230906/b230906.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 20*a(n-1) -174*a(n-2) +877*a(n-3) -2835*a(n-4) +6037*a(n-5) -8100*a(n-6) +5354*a(n-7) +1632*a(n-8) -5940*a(n-9) +3068*a(n-10) +2069*a(n-11) -3724*a(n-12) +2559*a(n-13) +882*a(n-14) -5020*a(n-15) +2708*a(n-16) +3962*a(n-17) -3859*a(n-18) -890*a(n-19) +2032*a(n-20) -318*a(n-21) -643*a(n-22) +197*a(n-23) +81*a(n-24) -10*a(n-25) -35*a(n-26) +15*a(n-27) -a(n-28) for n>31
%e Some solutions for n=4
%e ..0..1..0..3....0..2..0..3....0..2..1..0....0..2..3..1....0..1..0..1
%e ..2..3..2..1....1..3..1..2....1..3..2..3....1..0..2..3....2..3..2..0
%e ..0..1..3..0....0..2..0..3....2..0..1..0....3..1..0..1....1..0..3..2
%e ..3..0..2..3....1..3..1..2....3..2..3..2....0..3..2..0....3..2..1..0
%K nonn
%O 1,2
%A _R. H. Hardin_, Nov 01 2013
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