Number of k < 2^n that are neither squarefree nor prime powers.

Terms

a(0) =1a(1) =5a(2) =16a(3) =37a(4) =83a(5) =178a(6) =374a(7) =772a(8) =1565a(9) =3160a(10) =6361a(11) =12770a(12) =25599a(13) =51265a(14) =102634a(15) =205374a(16) =410873a(17) =821924a(18) =1644070a(19) =3288433a(20) =6577231a(21) =13154868a(22) =26310347a(23) =52621521a(24) =105244142a(25) =210489792a(26) =420981295a(27) =841964929a(28) =1683933254a(29) =3367871086