Partial sums of binary rooted tree numbers.

Terms

a(0) =1a(1) =2a(2) =4a(3) =7a(4) =12a(5) =21a(6) =37a(7) =65a(8) =115a(9) =204a(10) =363a(11) =648a(12) =1158a(13) =2072a(14) =3711a(15) =6649a(16) =11918a(17) =21369a(18) =38321a(19) =68731a(20) =123286a(21) =221157a(22) =396743a(23) =711759a(24) =1276927a(25) =2290903a(26) =4110101a(27) =7373976a(28) =13229809a(29) =23735984