A228306 The Wiener index of the Kneser graph K(n,2) (n>=5).
75, 165, 315, 546, 882, 1350, 1980, 2805, 3861, 5187, 6825, 8820, 11220, 14076, 17442, 21375, 25935, 31185, 37191, 44022, 51750, 60450, 70200, 81081, 93177, 106575, 121365, 137640, 155496, 175032, 196350, 219555, 244755, 272061, 301587, 333450
Offset: 5
References
- R. Balakkrishnan, S. Francis Raj, The Wiener number of Kneser graphs, Discussiones Math, Graph Theory, 28, 2008, 219-228.
Links
- Eric Weisstein's World of Mathematics, Kneser Graph.
- Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
Crossrefs
Cf. A228307
Programs
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Maple
a := proc (n) options operator, arrow: (1/8)*n*(n-1)*(n-2)*(n+5) end proc: seq(a(n), n = 5 .. 40);
Formula
a(n) = (1/8)*n*(n-1)*(n-2)*(n+5).
G.f.: 3*x^5*(25-70*x+80*x^2-43*x^3+9*x^4)/(1-x)^5.
The Hosoya-Wiener polynomial of K(n,2) is (1/8)*n*(n-1)*(n-2)*t*(n-3+4*t).
Comments