Number of perifusenes with one internal vertex.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =6a(6) =24a(7) =109a(8) =477a(9) =2155a(10) =9647a(11) =43621a(12) =197767a(13) =901436a(14) =4125636a(15) =18964119a(16) =87508095a(17) =405289754a(18) =1883445328a(19) =8780346115a(20) =41052409755a(21) =192461618324a(22) =904573028990