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A166408 a(n) = floor(A166407(n)/3).

%I A166408 #11 May 09 2021 05:11:17
%S A166408 -1,0,0,1,-3,1,0,2,0,1,0,3,-10,0,0,3,0,2,0,4,0,1,0,5,-21,2,0,4,0,3,0,
%T A166408 2,0,1,0,7,0,0,0,5,-27,3,0,6,0,2,0,8,0,0,0,5,0,3,0,8,0,2,0,10,-55,2,0,
%U A166408 5,0,5,0,2,0,3,0,10,0,0,0,7,0,4,0,10,0,1,0,11,-78,2,0,2,0,5,0,8,0,2,0
%N A166408 a(n) = floor(A166407(n)/3).
%C A166408 See the conjecture in A166407. If true, then a(i) = A166406(i)/A005408(i), whenever i is not in A166101.
%o A166408 (Python)
%o A166408 from sympy import floor, jacobi_symbol as J
%o A166408 def a(n):
%o A166408     l=0
%o A166408     m=0
%o A166408     for i in range(1, 2*n + 2):
%o A166408         if J(i, 2*n + 1)==-1: l+=i
%o A166408         elif J(i, 2*n + 1)==1: m+=i
%o A166408     return floor(3*((l - m)/(2*n + 1)))//3
%o A166408 print([a(n) for n in range(101)]) # _Indranil Ghosh_, Jun 12 2017
%Y A166408 A165951(n)=a(A102781(n)) for n>=2.
%K A166408 sign
%O A166408 0,5
%A A166408 _Antti Karttunen_, Oct 21 2009