A lobster graph, lobster tree, or simply "lobster," is a tree having the property that the removal of leaf nodes leaves a caterpillar
graph (Gallian 2007). The numbers of lobsters on 
, 2, ... are 1, 1, 1, 2, 3, 6, 11, 23, 47, 105, 231, 532,
1224, 2872, ... (OEIS A130131), and the corresponding
numbers of nonlobsters are 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 4, 19, 77, 287, ... (OEIS
A130132; the first few of which are illustrated
above). Precomputed properties of a number of lobster trees are implemented in the
Wolfram Language as GraphData["Lobster"].
