1,2

S. Janson, The Wiener index of simply generated random trees, Random Structures Algorithms 22 (2003) 337-358.

E. M. Wright, The number of connected sparsely edged graphs, J. Graph Theory 1 (1977) 317-330.

S. Janson and P. Chassaing, The center of mass of the ISE and the Wiener index of trees.

S. R. Finch, Shapes of binary trees

With a(0) = -1/2 one has for n > 0 the recurrence a(n) = 2*(5*n-4)*(5*n-6)*a(n-1)+sum(a(k)*a(n-k), k=1..n-1)

a(2)=2*(10-4)*(10-6)*a(1)+a(1)=49 since a(1)=1

Cf. A062980.

Sequence in context: A130416 A006692 A014801 this_sequence A145251 A013741 A100418

Adjacent sequences: A094196 A094197 A094198 this_sequence A094200 A094201 A094202

nonn

S. R. Finch (Steven.Finch(AT)inria.fr), May 25 2004