
EXAMPLE

For n=4 the "paw" graph has a(4)=5 fundamentally different labelings, namely with edges
04,03,02,23 or
04,03,02,34 or
04,03,13,01 or
04,03,13,34 or
04,03,24,34.
The other six graphs with four vertices are either ungraceful (2K_1) or uniquely graceful (K_1,3, K_4, C_4, P_4) or have fewer than 5 (K_1,1,2 has 4).
For n=5 the "dart" has a(5)=26 fundamentally different labelings.
