A tripod is a tree having exactly three tree leaves (Pirnazar and Ullman 2002). The numbers of tripods on , 2, ... vertices, counted
up to graph isomorphism, are 0, 0, 0, 1, 1,
2, 3, 4, 5, 7, 8, 10, 12, 14, 16, ... (OEIS A001399),
the first of which are illustrated above. For
, the count is
for the integer sequence
in OEIS A001399.
A list of tripods on small numbers of vertices is implemented in the Wolfram Language as GraphData["Tripod"].