A122681 Sum of the Wiener indices of all trees having n vertices.

0, 1, 4, 19, 54, 180, 508, 1533, 4332, 13041, 37492, 111367, 326636, 968802, 2858460, 8483290, 25113618, 74512947, 220885446, 655274837, 1943117294, 5763235194, 17089323366, 50673594159, 150232437482, 445359235627, 1320070201468

Offset

1,3

Comments

C program, see the first Bomfim link, around the function Gen() of Gang Li & Frank Ruskey. - Washington Bomfim, Feb 23 2011

Links

Table of n, a(n) for n=1..27.

W. Bomfim, C program

Stephan Wagner, Graph-theoretical enumeration and digital expansions: an analytic approach, Dissertation, Fakult. f. Tech. Math. u. Tech. Physik, Tech. Univ. Graz, Austria, Feb. 2006, page 31

Stephan Wagner, On the average Wiener index of degree-restricted trees, Australas. J. Combinat. 37 (2007) 187, Table 2

Example

a(4)=19; indeed, there are 2 trees on 4 vertices: the path abcd with Wiener index 1+1+1+2+2+3=10 and the star tree on 4 vertices with Wiener index 1+1+1+2+2+2 = 9. - Emeric Deutsch, Feb 20 2016

Crossrefs

Cf. A000055.

Sequence in context: A253008 A186310 A122684 * A215862 A174612 A020496

Adjacent sequences: A122678 A122679 A122680 * A122682 A122683 A122684

Keyword

nonn

Author

N. J. A. Sloane, Sep 23 2006

Extensions

a(11)-a(27) from Washington Bomfim, Feb 23 2011

Name edited by Emeric Deutsch, Feb 20 2016

Status

approved