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A112055 a(n) = A112054(n)/6. 3

%I

%S 2,3,5,7,8,12,13,15,17,18,20,22,23,27,28,30,32,33,35,37,38,40,42,43,

%T 47,48,50,52,53,55,57,58,62,63,65,67,68,70,72,73,75,77,78,82,83,85,87,

%U 88,90,92,93,97,98,100,102,103,107,108,110,112,113,117,118,120,122

%N a(n) = A112054(n)/6.

%t a112046[n_]:=Block[{i=1}, While[JacobiSymbol[i, 2n + 1]==1, i++]; i]; Select[Range[1000], a112046[2#] - a112046[2# - 1] != 0 &]/6 (* _Indranil Ghosh_, May 25 2017 *)

%o (Python)

%o from sympy import jacobi_symbol as J

%o def a112046(n):

%o i=1

%o while True:

%o if J(i, 2*n + 1)!=1: return i

%o else: i+=1

%o def a(n): return a112046(2*n) - a112046(2*n - 1)

%o print([n//6 for n in range(1, 201) if a(n)!=0]) # _Indranil Ghosh_, May 25 2017

%Y Cf. A112054, A112082 (complement), A112085 (first differences).

%K nonn

%O 1,1

%A _Antti Karttunen_, Aug 27 2005

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Last modified July 31 14:33 EDT 2021. Contains 346374 sequences. (Running on oeis4.)