Endpoints in trees with n nodes.

Terms

a(0) =1a(1) =2a(2) =2a(3) =5a(4) =9a(5) =21a(6) =43a(7) =101a(8) =226a(9) =556a(10) =1333a(11) =3365a(12) =8500a(13) =22007a(14) =57258a(15) =151264a(16) =401761a(17) =1077063a(18) =2902599a(19) =7871250a(20) =21440642a(21) =58672589a(22) =161155637a(23) =444240627a(24) =1228400744a(25) =3406668865a(26) =9472308269a(27) =26402207803a(28) =73755064178