Number of trees with 2-colored leaves.

Terms

a(0) =1a(1) =2a(2) =3a(3) =3a(4) =7a(5) =14a(6) =35a(7) =85a(8) =231a(9) =633a(10) =1845a(11) =5461a(12) =16707a(13) =51945a(14) =164695a(15) =529077a(16) =1722279a(17) =5664794a(18) =18813369a(19) =62996850a(20) =212533226a(21) =721792761a(22) =2466135375a(23) =8471967938a(24) =29249059293a(25) =101440962296a(26) =353289339927