Number of primes in level n of the tree generated at A234960.

Terms

a(0) =1a(1) =2a(2) =2a(3) =4a(4) =6a(5) =9a(6) =15a(7) =22a(8) =34a(9) =55a(10) =84a(11) =140a(12) =240a(13) =386a(14) =657a(15) =1097a(16) =1788a(17) =2968a(18) =4949a(19) =8182a(20) =13678a(21) =22867a(22) =38003a(23) =63339a(24) =105786a(25) =175926a(26) =293583a(27) =490270a(28) =818524a(29) =1366054