Reversion of Liouville's lambda function A008836.

Terms

a(0) =1a(1) =1a(2) =3a(3) =9a(4) =33a(5) =125a(6) =503a(7) =2083a(8) =8867a(9) =38477a(10) =169711a(11) =758369a(12) =3426415a(13) =15625647a(14) =71831229a(15) =332509595a(16) =1548599571a(17) =7251200053a(18) =34116127377a(19) =161202535685a(20) =764648531325