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

2,1

Comments

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

a(p) = p for all primes p.

Links

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

Example

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

Prog

(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

Crossrefs

Cf. A064920, A064922, A064917.

Sequence in context: A152984 A177980 A215405 * A064917 A154727 A323075

Adjacent sequences: A064918 A064919 A064920 * A064922 A064923 A064924

Keyword

nonn

Author

Reinhard Zumkeller, Oct 14 2001

Status

approved