A173950 a(n) = 1 if 6 divides (prime(n) + 1), a(n) = -1 if 6 divides (prime(n) - 1), a(n) = 0 otherwise.

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

Offset

1

Comments

Equals -A134323 except for the first term. - M. F. Hasler, Oct 09 2011

Links

Table of n, a(n) for n=1..100.

Formula

a(n) = -A134323(n) for n > 1. - M. F. Hasler, Oct 09 2011

a(n) = -Kronecker(-12, prime(n)) = -Kronecker(prime(n), 12) = -A134667(prime(n)). - Jianing Song, Mar 17 2019

Mathematica

Table[Which[Divisible[Prime[n]+1, 6], 1, Divisible[Prime[n]-1, 6], -1, True, 0], {n, 150}] (* Harvey P. Dale, Apr 24 2019 *)

Prog

(PARI) (From 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. A134323, A099618, A132194.

Cf. also A112632, A134667, A174695, A107323.

Sequence in context: A179770 A189078 A257834 * A157928 A159075 A178333

Adjacent sequences: A173947 A173948 A173949 * A173951 A173952 A173953

Keyword

sign

Author

Giovanni Teofilatto, Nov 26 2010

Status

approved