1. One and only one route exists on all edges of G
2. Terminals of two different routes don't meet on the same point
Table of n, a(n) for n=1..2.
Sequence in context: A005832 A195501 A075768 * A086895 A293241 A220646
Adjacent sequences: A135439 A135440 A135441 * A135443 A135444 A135445
Yasutoshi Kohmoto, Feb 18 2008