Number of trees T of order n such that W(T) = W(L(L(T))) where W(G) and L(G) are the Wiener index and line graph of a graph G.
A051175
Number of trees T of order n such that W(T) = W(L(L(T))) where W(G) and L(G) are the Wiener index and line graph of a graph G.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =1a(9) =1a(10) =1a(11) =0a(12) =7a(13) =8a(14) =22a(15) =25a(16) =66a(17) =73a(18) =204a(19) =231a(20) =513a(21) =576a(22) =1520a(23) =1715a(24) =3763a(25) =4085
External references
- oeis: A051175