Number of unrooted binary leaf-multi-labeled trees with n leaves on the label set [2], with each label used at least once.
A220829
Number of unrooted binary leaf-multi-labeled trees with n leaves on the label set [2], with each label used at least once.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =4a(4) =10a(5) =27a(6) =74a(7) =226a(8) =710a(9) =2354a(10) =8010a(11) =28189a(12) =101094a(13) =370119a(14) =1375198a(15) =5181003a(16) =19740940a(17) =75990173a(18) =295100800a(19) =1155106357a(20) =4553312866a(21) =18063117153a(22) =72069297826a(23) =289053128879
External references
- oeis: A220829