A107279 a(n) = 1 if n is an odd prime, a(n) = 2 if n is a nonzero even number, otherwise a(n) = 0.

0, 0, 2, 1, 2, 1, 2, 1, 2, 0, 2, 1, 2, 1, 2, 0, 2, 1, 2, 1, 2, 0, 2, 1, 2, 0, 2, 0, 2, 1, 2, 1, 2, 0, 2, 0, 2, 1, 2, 0, 2, 1, 2, 1, 2, 0, 2, 1, 2, 0, 2, 0, 2, 1, 2, 0, 2, 0, 2, 1, 2, 1, 2, 0, 2, 0, 2, 1, 2, 0, 2, 1, 2, 1, 2, 0, 2, 0, 2, 1, 2, 0, 2, 1, 2, 0, 2, 0, 2, 1, 2, 0, 2, 0, 2, 0, 2, 1, 2, 0

Offset: 0

Author

Giovanni Teofilatto, May 19 2005

Keywords

• easy
• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 0..5000

Crossrefs

Cf. A010051, A105661.

Programs

Mathematica

Table[ If[n==0,0,If[EvenQ[n], 2,If[PrimeQ[n], 1, 0]]], {n, 0, 99}] (* James C. McMahon, Feb 10 2024 *)

Scheme

(define (A107279 n) (cond ((<= n 1) 0) ((even? n) 2) (else (A010051 n)))) ;; Antti Karttunen, Sep 14 2017

Extensions

Description corrected by Antti Karttunen, Sep 14 2017