OFFSET
1,2
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
Sum_{n>=1} 1/a(n) = 1 + Sum_{k>=2} mu(k)*(1-zeta(k)*(2^k-1)/2^k) = 1.2890375574... - Amiram Eldar, Dec 19 2020
MAPLE
q:= n-> n=1 or n::odd and igcd(seq(i[2], i=ifactors(n)[2]))>1:
select(q, [$1..6000])[]; # Alois P. Heinz, May 04 2022
MATHEMATICA
Take[Union[Flatten[Table[a^b, {a, 1, 99, 2}, {b, 2, 15}]]], 50] (* Alonso del Arte, Nov 22 2011 *)
PROG
(Haskell)
a075109 n = a075109_list !! (n-1)
a075109_list = filter odd a001597_list -- Reinhard Zumkeller, Oct 04 2012
(Magma) [1] cat [n : n in [3..6000 by 2] | IsPower(n) ]; // Vincenzo Librandi, Mar 31 2014
(PARI) isok(m) = (m==1) || ((m%2) && ispower(m)); \\ Michel Marcus, May 04 2022
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Zak Seidov, Oct 11 2002
EXTENSIONS
Definition clarified by N. J. A. Sloane, Dec 25 2021
STATUS
approved