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%I #4 Apr 18 2012 05:42:17
%S 80,712,6328,56184,498328,4415576,39087704,345688344,3054441560,
%T 26964466456,237834515800,2095997626392,18456488165848,
%U 162389882849432,1427675316724184,12542069778534552,110099840447243864
%N Number of -4..4 arrays x(i) of n+1 elements i=1..n+1 with x(i)+x(j), x(i+1)+x(j+1), -(x(i)+x(j+1)), and -(x(i+1)+x(j)) having two, three or four distinct values for every i<=n and j<=n
%H R. H. Hardin, <a href="/A211693/b211693.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 40*a(n-1) -630*a(n-2) +4800*a(n-3) -16675*a(n-4) +13128*a(n-5) +34290*a(n-6) +17120*a(n-7) +3176*a(n-8) +192*a(n-9)
%e Some solutions for n=5
%e .-4...-1...-3...-4...-3...-1...-3...-3...-4...-1...-2...-2...-1...-4...-4...-4
%e .-3....2...-3....4....2...-3....4....2....0....0...-1....1....1...-1....1...-2
%e .-3...-2...-2...-2...-1...-1...-2...-4...-4...-2...-4...-4...-4...-3...-2...-2
%e ..2...-3...-3....4....0....4....4...-1....3...-1...-3....0...-1...-2....3....2
%e .-3...-4....2...-4...-2....4...-4....2...-1...-3...-4...-3....4....0...-1...-2
%e ..2...-3....4....4....1....2...-4...-4....3...-2...-1....2....0....1....2...-4
%K nonn
%O 1,1
%A _R. H. Hardin_ Apr 18 2012
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