
EXAMPLE

The following list shows all optimal graphs (i.e., graphs having n nodes and a(n) maximal acyclic subgraphs) for 1 <= n <= 9. Here, CK(n_1, ..., n_k) is the graph obtained by arranging complete graphs of orders n_1, ..., n_k (in that order) in a cycle, and joining all nodes in neighboring parts with edges. (The graph in the paper by Fomin, Gaspers, Pyatkin, and Razgon, which shows that a(10) >= 105, is CK(2, 2, 2, 2, 2).)
n = 1: the 1node graph;
n = 2: the complete graph and the empty graph;
3 <= n <= 6: the complete graph;
n = 7: CK(1, 2, 2, 2);
n = 8: CK(1, 2, 1, 2, 2);
n = 9: CK(1, 2, 2, 1, 3).
