OFFSET
1,1
COMMENTS
Subsequence of A322448 and first differs from it at n = 138: A322448(138) = 2592 = 2^5 * 3^4 is not a term of this sequence.
The asymptotic density of this sequence is d = Sum_{k composite} (1/zeta(k+1) - 1/zeta(k)) = 0.05296279266796920306... . The asymptotic density of this sequence within the nonsquarefree numbers (A013929) is d / (1 - 1/zeta(2)) = 0.13508404411123191108... .
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MAPLE
filter:= proc(n) local m;
m:= max(ifactors(n)[2][.., 2]);
m > 1 and not isprime(m)
end proc:
select(filter, [$1..10000]); # Robert Israel, Jul 14 2024
MATHEMATICA
Select[Range[1200], CompositeQ[Max[FactorInteger[#][[;; , 2]]]] &]
PROG
(PARI) iscomposite(n) = n > 1 && !isprime(n);
is(n) = n > 1 && iscomposite(vecmax(factor(n)[, 2]));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Amiram Eldar, Jul 12 2024
STATUS
approved