Number of carbon trees with n carbon atoms.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =10a(5) =22a(6) =60a(7) =158a(8) =439a(9) =1229a(10) =3525a(11) =10178a(12) =29802a(13) =87862a(14) =261204a(15) =781198a(16) =2350249a(17) =7105081a(18) =21577415a(19) =65787902a(20) =201313311a(21) =618040002a(22) =1903102730a(23) =5876174472a(24) =18189503139a(25) =56435742554a(26) =175477142565a(27) =546703920430