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%I #24 May 21 2019 17:10:31
%S 0,0,1,-1,1,-1,1,-1,1,1,-1,-1,1,-1,1,1,1,-1,-1,1,-1,-1,1,1,-1,1,-1,1,
%T -1,1,-1,1,1,-1,1,-1,-1,-1,1,1,1,-1,1,-1,1,-1,-1,-1,1,-1,1,1,-1,1,1,1,
%U 1,-1,-1,1,-1,1,-1,1,-1,1,-1,-1,1,-1,1,1,-1,-1,-1,1,1,-1,1,-1,1,-1,1,-1,-1,1,1,-1,1,-1,1,1,-1,1,-1,1,1,1,-1,-1
%N a(n) = 1 if 6 divides (prime(n) + 1), a(n) = -1 if 6 divides (prime(n) - 1), a(n) = 0 otherwise.
%C Equals -A134323 except for the first term. - _M. F. Hasler_, Oct 09 2011
%F a(n) = -A134323(n) for n > 1. - _M. F. Hasler_, Oct 09 2011
%F a(n) = -Kronecker(-12, prime(n)) = -Kronecker(prime(n), 12) = -A134667(prime(n)). - _Jianing Song_, Mar 17 2019
%t Table[Which[Divisible[Prime[n]+1,6],1,Divisible[Prime[n]-1,6],-1,True,0],{n,150}] (* _Harvey P. Dale_, Apr 24 2019 *)
%o (PARI) (From _M. F. Hasler_, Oct 09 2011) (Start)
%o A173950(n)=if(prime(n)%6==1,-1,n>2)
%o A173950(n)=(-1)^(prime(n)%3)*(n>2)
%o A173950(n)=[-1,0,0,0,1][prime(n)%6]
%o A173950(n)=if(n>2,prime(n)%6-3)/2 \\ (End)
%Y Cf. A134323, A099618, A132194.
%Y Cf. also A112632, A134667, A174695, A107323.
%K sign
%O 1
%A _Giovanni Teofilatto_, Nov 26 2010
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