a(1) = 1; a(n+1) = Sum_{d|n, gcd(d, n/d) = 1} a(n/d) * a(d).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =8a(5) =16a(6) =36a(7) =72a(8) =144a(9) =288a(10) =592a(11) =1184a(12) =2384a(13) =4768a(14) =9608a(15) =19248a(16) =38496a(17) =76992a(18) =154272a(19) =308544a(20) =617152a(21) =1234448a(22) =2470080a(23) =4940160a(24) =9880608a(25) =19761216a(26) =39527200a(27) =79054400a(28) =158109088a(29) =316218176