Number of perfect powers (A001597) < 2^n.

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =4a(5) =7a(6) =10a(7) =15a(8) =22a(9) =30a(10) =41a(11) =57a(12) =81a(13) =113a(14) =155a(15) =216a(16) =298a(17) =416a(18) =582a(19) =813a(20) =1135a(21) =1588a(22) =2223a(23) =3115a(24) =4368a(25) =6135a(26) =8622a(27) =12127a(28) =17063a(29) =24022