A077008 Legendre symbol (-1,p) where p is the n-th prime.

-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, 1, -1

Offset

2,1

Comments

Same as A070750 (where additionally a(1)=0 is included). - Joerg Arndt, Apr 21 2016

Links

Table of n, a(n) for n=2..101.

Formula

a(n) = A070750(n). - Joerg Arndt, Apr 21 2016

Mathematica

p = Table[Prime[i], {i, 2, 101}]; Table[JacobiSymbol[p[[j]] - 1, p[[j]]], {j, 1, 100}]
a[n_] := (-1)^((Prime[n]-1)/2); Table[a[n], {n, 2, 101}] (* Jean-François Alcover, Apr 20 2016 *)

Prog

(PARI) a(n)=kronecker(-1, prime(n)) \\ Charles R Greathouse IV, Jun 13 2013
(PARI) a(n)=if(prime(n)%4==1, 1, -1) \\ Charles R Greathouse IV, Jun 13 2013

Crossrefs

Cf. A070750, A039702.

Sequence in context: A309873 A162511 A157895 * A158387 A265643 A283131

Adjacent sequences: A077005 A077006 A077007 * A077009 A077010 A077011

Keyword

sign,easy

Author

Joseph L. Pe, Nov 28 2002

Extensions

Replaced "(p-1,p)" by "(-1,p)" in name, Joerg Arndt, Apr 21 2016

Status

approved