OFFSET
1,2
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
PROG
(PARI)
A020639(n) = if(1==n, n, vecmin(factor(n)[, 1]));
A007947(n) = factorback(factorint(n)[, 1]); \\ From Andrew Lelechenko, May 09 2014
n=0; k=1; while(k <= 10000, n=n+1; if(isA285100(n), write("b285100.txt", k, " ", n); k=k+1));
(Scheme, with Antti Karttunen's IntSeq-library)
(Python)
from operator import mul
from sympy import primefactors
from functools import reduce
def a007947(n): return 1 if n<2 else reduce(mul, primefactors(n))
def a020639(n): return 1 if n==1 else primefactors(n)[0]
def a065642(n):
if n==1: return 1
r=a007947(n)
n += r
while a007947(n)!=r:
n+=r
return n
print([n for n in range(1, 102) if a065642(n) == n*a020639(n)]) # Indranil Ghosh, May 24 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 19 2017
STATUS
approved