Number of unlabeled forests of rooted trees with 2n edges and n connected components, in which the outdegree of each node is <= 2 and the symmetric group acts on the components.
A305839
Number of unlabeled forests of rooted trees with 2n edges and n connected components, in which the outdegree of each node is <= 2 and the symmetric group acts on the components.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =6a(4) =15a(5) =32a(6) =77a(7) =172a(8) =405a(9) =930a(10) =2180a(11) =5070a(12) =11914a(13) =27929a(14) =65829a(15) =155202a(16) =367053a(17) =868990a(18) =2061723a(19) =4897502a(20) =11652547a(21) =27757960a(22) =66210042a(23) =158103242a(24) =377957299a(25) =904439542a(26) =2166408422a(27) =5193894809a(28) =12463003846a(29) =29929966312
External references
- oeis: A305839