Number of identity trees with n nodes where the maximal outdegree (branching factor) equals 2.

Terms

a(0) =1a(1) =2a(2) =5a(3) =10a(4) =21a(5) =42a(6) =87a(7) =178a(8) =371a(9) =773a(10) =1630a(11) =3447a(12) =7346a(13) =15712a(14) =33790a(15) =72922a(16) =158020a(17) =343494a(18) =749101a(19) =1638102a(20) =3591723a(21) =7893801a(22) =17387930a(23) =38379199a(24) =84875595a(25) =188036829a(26) =417284180a(27) =927469844a(28) =2064465340a(29) =4601670624