A064921 Iterate A064920 until a prime is reached.

2, 3, 3, 5, 3, 7, 5, 5, 3, 11, 3, 13, 5, 7, 5, 17, 5, 19, 5, 5, 3, 23, 3, 5, 5, 11, 3, 29, 3, 31, 17, 13, 5, 11, 5, 37, 5, 7, 3, 41, 3, 43, 5, 13, 3, 47, 5, 13, 5, 19, 5, 53, 5, 7, 5, 5, 3, 59, 5, 61, 17, 7, 13, 17, 5, 67, 5, 5, 5, 71, 5, 73, 5, 19, 3, 17, 5, 79, 5, 29, 3, 83, 5, 5, 5, 31, 5

Offset: 2

Author

Reinhard Zumkeller, Oct 14 2001

Keywords

• nonn

Comments

Well defined since A064920(n) < n for nonprimes.

a(p) = p for all primes p.

Examples

			a(18) = 5 as A064920(18) = 8 and A064920(8) = 5.
		

Links

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

Crossrefs

Cf. A064920, A064922, A064917.

Programs

PARI

gpf(n)= { local(f); f=factor(n)~; return(f[1, length(f)]) } { for (n=2, 1000, m=n; while (!isprime(m), g=gpf(m); m=m / g + g - 1); write("b064921.txt", n, " ", m) ) } \\ Harry J. Smith, Sep 29 2009