A227625 Indicator sequence of primes p > 3: k = p mod 6, if k = 5 then a(n) = -1, if k = 1 then a(n) = 1 else a(n) = 0, a(2) = -1, a(3) = 1.

0, -1, 1, 0, -1, 0, 1, 0, 0, 0, -1, 0, 1, 0, 0, 0, -1, 0, 1, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, -1, 0, 1, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, -1, 0, 0

Offset

1

Links

Freimut Marschner, Table of n, a(n) for n = 1..1900

Mathematica

Join[{0, -1, 1}, Table[If[!PrimeQ[n], 0, If[Mod[n, 6] = 1, 1, -1], {n, 4, 100}]] (* T. D. Noe, Jul 20 2013 *)

Crossrefs

Cf. A129950 (indicator function of twin primes), A010051 (characteristic function of primes: 1 if n is prime else 0).

Sequence in context: A286487 A122257 A332219 * A373497 A129950 A010051

Adjacent sequences: A227622 A227623 A227624 * A227626 A227627 A227628

Keyword

sign

Author

Freimut Marschner, Jul 18 2013

Status

approved