Number of cubes of primes <= 2^n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =2a(6) =2a(7) =3a(8) =3a(9) =4a(10) =4a(11) =5a(12) =6a(13) =8a(14) =9a(15) =11a(16) =12a(17) =15a(18) =18a(19) =22a(20) =26a(21) =31a(22) =37a(23) =46a(24) =54a(25) =66a(26) =79a(27) =97a(28) =117a(29) =141