OFFSET
1,1
COMMENTS
The Wiener index of a connected graph is the sum of distances between all unordered pairs of vertices in the graph.
LINKS
T. Mansour and M. Schork, Wiener, hyper-Wiener, detour and hyper-detour indices of bridge and chain graphs, J. Math. Chemistry, 47, 2010, 72-98 (see Example 5.6).
FORMULA
EXAMPLE
a(1)=8 because in the graph <> with vertices a,b,c,d we have 4 distances equal to 1 (the edges) and 2 distances equal to 2 (ac and bd); 4*1 + 2*2 = 8.
MAPLE
seq(n*(2+3*n+3*n^2), n=1..40);
CROSSREFS
KEYWORD
nonn
AUTHOR
Emeric Deutsch, Sep 06 2008
STATUS
approved