OFFSET
1,1
COMMENTS
Perfect powers are of the form m^k where m > 0 and k > 1 (A001597).
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
10 is in the sequence since it is even and is not a power of an integer. 17 is not in the sequence since it is odd, and 36 is not in the sequence since it is a power of an integer (36 = 6^2).
MAPLE
N:= 1000:
S:={seq(i, i=2..N, 2)} minus {seq(seq(e^m, m=2..floor(log[e](N))), e=2..floor(sqrt(N)), 2)}:
sort(convert(S, list)); # Robert Israel, Jan 24 2019
MATHEMATICA
radQ[n_]:=Or[n==1, GCD@@FactorInteger[n][[All, 2]]==1];
Select[Range[200], EvenQ[#]&&radQ[#]&]
PROG
(PARI) isok(n) = !(n % 2) && !ispower(n); \\ Michel Marcus, Jun 08 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jun 07 2018
STATUS
approved