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%I #9 Mar 16 2018 10:01:20
%S 2,14,23,67,100,202,281,479,636,971,1243,1770,2205,2980,3630,4725,
%T 5654,7140,8415,10381,12082,14614,16823,20027,22840,26817,30331,35204,
%U 39531,45416,50668,57705,64010,72330,79815,89575,98384,109730,120005,133111
%N Number of nondecreasing -2..2 vectors of length n whose dot product with some other -2..2 vector equals n.
%C Column 2 of A226340.
%H R. H. Hardin, <a href="/A226334/b226334.txt">Table of n, a(n) for n = 1..144</a>
%F Conjectures from _Colin Barker_, Mar 16 2018: (Start)
%F G.f.: x*(2 + 12*x + 5*x^2 + 20*x^3 + 13*x^4 + 2*x^5 + 12*x^6 - 2*x^7 + x^9 - 2*x^10 - x^11 + x^12) / ((1 - x)^5*(1 + x)^4*(1 + x^2)^2).
%F a(n) = a(n-1) + 2*a(n-2) - 2*a(n-3) + a(n-4) - a(n-5) - 4*a(n-6) + 4*a(n-7) + a(n-8) - a(n-9) + 2*a(n-10) - 2*a(n-11) - a(n-12) + a(n-13) for n>13.
%F (End)
%e Some solutions for n=3:
%e .-1...-1...-1....0...-1...-2...-1...-2....1....1...-2...-1...-1...-1....1...-2
%e ..1...-1....2....1....1...-1...-1...-1....1....2...-2....0...-1....0....1....1
%e ..2....1....2....1....1....0....0....1....2....2....1....1....2....2....1....1
%Y Cf. A226340.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jun 04 2013
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