Bisection of A086652.

Terms

a(0) =13a(1) =58a(2) =244a(3) =1000a(4) =4048a(5) =16288a(6) =65344a(7) =261760a(8) =1047808a(9) =4192768a(10) =16774144a(11) =67102720a(12) =268423168a(13) =1073717248a(14) =4294918144a(15) =17179770880a(16) =68719280128a(17) =274877513728