OFFSET
1,2
COMMENTS
This endomorphism a:N->N replaces the smallest prime factor in n with the prime following it. For coherence, a(1)=1. Some interesting properties: a(n)>=n, with 1 being the only invariant element, bigomega(a(n)) = bigomega(n), the orbits of all numbers m having the largest prime factor p are congruent with p^bigomega(m); etc.
LINKS
Stanislav Sykora, Table of n, a(n) for n = 1..10000
S. Sykora, PARI scripts: PrimesRelatedFunctions
EXAMPLE
a(21)=a(3*7)=5*7=35.
PROG
(PARI) A233570(n)={local(p); p=SmallestPrimeFactor(n); return
((n\p)*FollowingPrime(p))} \\ See the links for the auxiliary scripts
CROSSREFS
KEYWORD
nonn
AUTHOR
Stanislav Sykora, Dec 13 2013
STATUS
approved