Numbers of unlabeled graphs with n vertices and 3 unicyclic components.

Terms

a(0) =1a(1) =2a(2) =8a(3) =27a(4) =89a(5) =289a(6) =938a(7) =2985a(8) =9456a(9) =29722a(10) =92842a(11) =288509a(12) =892506a(13) =2749940a(14) =8443504a(15) =25845735a(16) =78897469a(17) =240259510a(18) =730040882a(19) =2213910727a(20) =6701939407a(21) =20255424836a(22) =61128717826a(23) =184233427305a(24) =554574518396