OFFSET
1,2
COMMENTS
Except for 1, terms are not squarefree, that is, all terms > 1 form a subsequence of A013929.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..500
FORMULA
Numbers k such that the set of prime factors of k is a subset of the set of prime factors of primepi(k).
MATHEMATICA
Select[Range[2^14], PowerMod[PrimePi[#], Prime[#], #] == 0 &] (* Michael De Vlieger, May 14 2018 *)
PROG
(PARI) isok(n) = !(primepi(n)^prime(n) % n); \\ Michel Marcus, May 14 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Chai Wah Wu, Apr 25 2018
STATUS
approved