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A368714
Numbers whose maximal exponent in their prime factorization is even.
13
1, 4, 9, 12, 16, 18, 20, 25, 28, 36, 44, 45, 48, 49, 50, 52, 60, 63, 64, 68, 75, 76, 80, 81, 84, 90, 92, 98, 99, 100, 112, 116, 117, 121, 124, 126, 132, 140, 144, 147, 148, 150, 153, 156, 162, 164, 169, 171, 172, 175, 176, 180, 188, 192, 196, 198, 204, 207, 208
OFFSET
1,2
COMMENTS
First differs from A240112 at n = 30.
Numbers k such that A051903(k) is even.
The asymptotic density of this sequence is Sum_{k>=2} (-1)^k * (1 - 1/zeta(k)) = 0.27591672059822700769... .
LINKS
MATHEMATICA
Select[Range[210], # == 1 || EvenQ[Max[FactorInteger[#][[;; , 2]]]] &]
PROG
(PARI) lista(kmax) = for(k = 1, kmax, if(k == 1 || !(vecmax(factor(k)[, 2])%2), print1(k, ", ")));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Amiram Eldar, Jan 04 2024
STATUS
approved