OFFSET
1,2
COMMENTS
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
FORMULA
Sum_{n>=1} 1/a(n) = 1 + Sum_{k in A024619} P(k) = 1.018407114609068368636..., where P is the prime zeta function. - Amiram Eldar, Nov 26 2020
EXAMPLE
2^12 = 4096. Since 2 is prime, and since 12 is not a power of a prime, then 4096 is in this sequence.
PROG
(PARI) isok(k) = if(k==1, return(1)); my(q=isprimepower(k)); (q>1) && !isprimepower(q); \\ Michel Marcus, Nov 26 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Aug 13 2009
EXTENSIONS
Extended beyond 16384 by R. J. Mathar, Sep 27 2009
STATUS
approved