OFFSET
1,3
LINKS
Eric Weisstein's World of Mathematics, Graceful Graph
Eric Weisstein's World of Mathematics, Isolated Point
EXAMPLE
1 edge: P_2
2 edges: P_3
3 edges: K_1,3 (claw), P_4, C_3
4 edges: fork graph, P_5, paw graph, C_4, S_5
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Jun 06 2019
EXTENSIONS
a(12) from Eric W. Weisstein, Jun 20 2019
STATUS
approved