The number of oriented star-like and star trees with n arcs.

Terms

a(0) =4a(1) =17a(2) =66a(3) =221a(4) =688a(5) =2034a(6) =5788a(7) =15998a(8) =43192a(9) =114496a(10) =298712a(11) =769340a(12) =1959064a(13) =4940761a(14) =12354210a(15) =30660947a(16) =75583868a(17) =185208833a(18) =451356846a(19) =1094522547a(20) =2642121008a(21) =6351335083a(22) =15208854510a(23) =36288478177a(24) =86295204732a(25) =204571273167a(26) =483532711338