Sum of all squarefree numbers from 2^(n-1) to 2^n - 1.

Terms

a(0) =1a(1) =5a(2) =18a(3) =63a(4) =218a(5) =891a(6) =3676a(7) =15137a(8) =60580a(9) =238672a(10) =953501a(11) =3826167a(12) =15308186a(13) =61204878a(14) =244709252a(15) =979285522a(16) =3917052950a(17) =15664274802a(18) =62663847447a(19) =250662444349