Bisection of A001615.

Terms

a(0) =1a(1) =4a(2) =6a(3) =8a(4) =12a(5) =12a(6) =14a(7) =24a(8) =18a(9) =20a(10) =32a(11) =24a(12) =30a(13) =36a(14) =30a(15) =32a(16) =48a(17) =48a(18) =38a(19) =56a(20) =42a(21) =44a(22) =72a(23) =48a(24) =56a(25) =72a(26) =54a(27) =72a(28) =80a(29) =60