%I #4 Nov 25 2014 09:26:07
%S 13,117,761,5105,31525,177421,937817,4803653,24257725,121800949,
%T 610147053,3053493273,15274472475,76391277073,382008613455,
%U 1910192140573,9551389260819,47758200502193,238794678323345,1193984277090533
%N Number of length n+2 0..4 arrays with the sum of second differences multiplied by some arrangement of +-1 equal to zero
%C Column 4 of A250561
%H R. H. Hardin, <a href="/A250557/b250557.txt">Table of n, a(n) for n = 1..28</a>
%e Some solutions for n=6
%e ..0....0....2....0....2....0....1....1....1....2....2....2....1....0....1....0
%e ..3....0....2....2....1....1....0....1....2....0....1....0....0....3....4....0
%e ..4....2....3....0....0....0....2....2....3....0....4....2....4....2....4....4
%e ..4....2....3....1....2....0....4....2....4....2....3....2....4....2....2....4
%e ..3....4....3....2....4....2....2....4....1....0....3....2....4....3....3....0
%e ..4....1....1....2....0....4....1....1....0....3....2....1....1....4....1....1
%e ..1....4....2....3....1....4....1....3....4....1....4....4....0....3....0....0
%e ..2....2....4....3....4....1....2....1....1....3....3....0....3....4....1....0
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 25 2014
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