login
A064918
a(n) is the number of iterations of k -> A064916(k) to reach a prime, starting at n.
5
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
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
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 14 2001
STATUS
approved