Partial sums of floor(2^n/5).

Terms

a(0) =0a(1) =0a(2) =1a(3) =4a(4) =10a(5) =22a(6) =47a(7) =98a(8) =200a(9) =404a(10) =813a(11) =1632a(12) =3270a(13) =6546a(14) =13099a(15) =26206a(16) =52420a(17) =104848a(18) =209705a(19) =419420a(20) =838850a(21) =1677710a(22) =3355431a(23) =6710874a(24) =13421760a(25) =26843532a(26) =53687077a(27) =107374168a(28) =214748350a(29) =429496714