OFFSET
1,1
COMMENTS
A prime index of n is a number m such that prime(m) divides n.
MATHEMATICA
Prime/@Select[Range[100], Or[#===1, PrimePowerQ[#]]&]
PROG
(PARI) forprime(p=1, 500, if(p==2 || isprimepower(primepi(p)), print1(p, ", "))) \\ Felix Fröhlich, Apr 10 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Apr 08 2018
STATUS
approved