login
A302493
Prime numbers of prime-power index.
8
2, 3, 5, 7, 11, 17, 19, 23, 31, 41, 53, 59, 67, 83, 97, 103, 109, 127, 131, 157, 179, 191, 211, 227, 241, 277, 283, 311, 331, 353, 367, 401, 419, 431, 461, 509, 547, 563, 587, 599, 617, 661, 691, 709, 719, 739, 773, 797, 859, 877, 919, 967, 991, 1009, 1031
OFFSET
1,1
COMMENTS
A prime index of n is a number m such that prime(m) divides n.
FORMULA
a(n) = A000040(A000961(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
KEYWORD
nonn
AUTHOR
Gus Wiseman, Apr 08 2018
STATUS
approved