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 A173950 a(n)= 1 if 6 |  prime(n)+1, a(n) = -1 if 6 | prime(n)-1, a(n) = 0 otherwise. 2
 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, -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, -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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1 COMMENTS Equals -A134323 except for the first term. - M. F. Hasler, Oct 09 2011 LINKS FORMULA a(n)=-A134323(n) for n>1. - M. F. Hasler, Oct 09 2011 PROG (PARI) (Contribution by M. F. Hasler, Oct 09 2011) (Start) A173950(n)=if(prime(n)%6==1, -1, n>2) A173950(n)=(-1)^(prime(n)%3)*(n>2) A173950(n)=[-1, 0, 0, 0, 1][prime(n)%6] A173950(n)=if(n>2, prime(n)%6-3)/2  \\ (End) CROSSREFS Cf. A132194, A099618, A134323, A112632, A096630, A007352, A098044. Sequence in context: A288226 A189078 A257834 * A283020 A284683 A288673 Adjacent sequences:  A173947 A173948 A173949 * A173951 A173952 A173953 KEYWORD sign AUTHOR Giovanni Teofilatto, Nov 26 2010 STATUS approved

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