Number of connected line graphs with n nodes.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =12a(5) =30a(6) =79a(7) =227a(8) =710a(9) =2322a(10) =8071a(11) =29503a(12) =112822a(13) =450141a(14) =1867871a(15) =8037472a(16) =35787667a(17) =164551477a(18) =779945969a(19) =3804967442a(20) =19079312775a(21) =98211456209a(22) =518397621443