A064918 a(n) is the number of iterations of k -> A064916(k) to reach a prime, starting at n.

0, 0, 1, 0, 2, 0, 1, 1, 3, 0, 1, 0, 2, 1, 2, 0, 4, 0, 1, 2, 2, 0, 1, 2, 3, 1, 2, 0, 3, 0, 1, 1, 5, 1, 1, 0, 2, 2, 3, 0, 3, 0, 1, 1, 2, 0, 3, 1, 4, 1, 2, 0, 3, 2, 1, 3, 4, 0, 1, 0, 2, 1, 2, 1, 6, 0, 2, 3, 2, 0, 1, 0, 3, 2, 3, 1, 4, 0, 1, 1, 4, 0, 1, 3, 2, 1, 2, 0, 3, 1, 1, 2, 4, 1, 2, 0, 5, 2, 2, 0, 3, 0, 1, 1, 4

Offset

2,5

Comments

a(p) = 0 for all primes p.

Links

Harry J. Smith, Table of n, a(n) for n = 2..1000

Example

a(6) = 2 as A064916(A064916(6)) = A064916(4) = 3 = A064917(6).

Prog

(PARI) lpf(n)= { local(f); f=factor(n); return(f[1, 1]) } { for (n=2, 1000, m=n; a=0; while (!isprime(m), L=lpf(m); m=m / L + L - 1; a++); write("b064918.txt", n, " ", a) ) } \\ Harry J. Smith, Sep 29 2009

Crossrefs

Cf. A064916, A064917, A064922.

Sequence in context: A180243 A326728 A330944 * A323076 A286471 A176079

Adjacent sequences: A064915 A064916 A064917 * A064919 A064920 A064921

Keyword

nonn

Author

Reinhard Zumkeller, Oct 14 2001

Status

approved