OFFSET
1,1
LINKS
John Tyler Rascoe, Table of n, a(n) for n = 1..1000
EXAMPLE
20 is included because 5 is the largest prime dividing 20. And of the primes <= 5 (2,3,5), 2 and 5 (2 primes) divide 20, 3 (only 1 prime) does not divide 20.
PROG
(PARI) {m=270; v=vector(m); for(n=2, m, f=factor(n)[, 1]~; c=0; pc=0; forprime(p=2, vecmax(f), j=1; s=length(f); while(j<=s&&p!=f[j], j++); if(j<=s, c++); pc++); v[n]=sign(pc-2*c)); for(n=1, m, if(v[n]<0, print1(n, ", ")))} \\ Klaus Brockhaus, Aug 21 2005
(Python)
from itertools import count, islice
from sympy import sieve, factorint
def a_gen():
for n in count(2):
f = [sieve.search(i)[0] for i in factorint(n)]
if len(f) > f[-1]//2:
yield n
A111905_list = list(islice(a_gen(), 100)) # John Tyler Rascoe, Jun 22 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Aug 19 2005
EXTENSIONS
More terms from Klaus Brockhaus, Aug 21 2005
STATUS
approved