Primes p for which the period length of 1/p is a perfect power, A001597.

Terms

a(0) =3a(1) =17a(2) =73a(3) =101a(4) =137a(5) =163a(6) =257a(7) =353a(8) =449a(9) =577a(10) =641a(11) =751a(12) =757a(13) =883a(14) =1297a(15) =1409a(16) =1801a(17) =3137a(18) =3529a(19) =5477a(20) =7057a(21) =7351a(22) =8929a(23) =9397a(24) =10753a(25) =11831a(26) =12101a(27) =13457a(28) =13553a(29) =14401