OFFSET
1,1
COMMENTS
LINKS
Matthieu Pluntz, Table of n, a(n) for n = 1..10929 (up to a(n) = 2^21)
EXAMPLE
The sequence of terms together with their prime indices begins:
2: {1}
4: {1,1}
6: {1,2}
8: {1,1,1}
9: {2,2}
12: {1,1,2}
16: {1,1,1,1}
18: {1,2,2}
20: {1,1,3}
24: {1,1,1,2}
27: {2,2,2}
30: {1,2,3}
32: {1,1,1,1,1}
36: {1,1,2,2}
40: {1,1,1,3}
45: {2,2,3}
48: {1,1,1,1,2}
MAPLE
with(numtheory):
q:= n-> is(pi(max(factorset(n)))<=bigomega(n)):
select(q, [$2..300])[]; # Alois P. Heinz, Mar 07 2019
MATHEMATICA
Select[Range[2, 100], PrimePi[FactorInteger[#][[-1, 1]]]<=PrimeOmega[#]&]
PROG
(PARI) isok(m) = (m>1) && (primepi(vecmax(factor(m)[, 1])) <= bigomega(m)); \\ Michel Marcus, Nov 14 2022
(Python)
from sympy import factorint, primepi
def ok(n):
f = factorint(n)
return primepi(max(f)) <= sum(f.values())
print([k for k in range(2, 257) if ok(k)]) # Michael S. Branicky, Nov 15 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Mar 06 2019
STATUS
approved