Number of equicolored (unrooted) trees on 2n nodes.

Terms

a(0) =1a(1) =1a(2) =4a(3) =14a(4) =65a(5) =316a(6) =1742a(7) =10079a(8) =61680a(9) =391473a(10) =2565262a(11) =17237962a(12) =118341446a(13) =827194809a(14) =5872518213a(15) =42256545977a(16) =307681822711