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%I #8 Dec 11 2021 21:59:57
%S 12,22,50,90,192,360,752,1472,3060,6104,12596,25368,52230,106038,
%T 218204,445350,916598,1877598,3866920,7942794,16372182,33699352,
%U 69526894,143344944,296012610,611113112,1263073756,2610512928,5399923198
%N Number of -1..1 arrays x(0..n+2) of n+3 elements with zero sum and nonzero second and third differences.
%C Column 1 of A200204.
%H R. H. Hardin, <a href="/A200197/b200197.txt">Table of n, a(n) for n = 1..200</a>
%e Some solutions for n=3
%e ..0....1....0....0....1....0...-1...-1....0....1....0...-1...-1....1...-1...-1
%e ..0....0....0....1....0...-1....1....0....0....1....0....0....1....0...-1...-1
%e .-1....0....1....1....0....1...-1....0...-1....0....1....0....0....1....0....1
%e ..1...-1...-1...-1...-1....0....1....1....1....0....1....1....0...-1....0....0
%e ..0...-1....0...-1....0....1....0....0...-1...-1...-1...-1...-1...-1....1....1
%e ..0....1....0....0....0...-1....0....0....1...-1...-1....1....1....0....1....0
%Y Cf. A200204.
%K nonn
%O 1,1
%A _R. H. Hardin_ Nov 14 2011
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