OFFSET
2,1
REFERENCES
D. B. West, Introduction to Graph Theory, 2nd ed., Prentice-Hall, NJ, 2001, p. 205.
LINKS
R. Balakrishnan, S. F. Raj, The Wiener number of powers of the Mycielskian, Discussiones Math. Graph Theory, 30, 2010, 489-498 (see Theorem 2.1).
Index entries for linear recurrences with constant coefficients, signature (3, -3, 1).
FORMULA
a(2)=15; a(n) = 6n^2 - 13n + 18 (n>=3).
G.f.: x^2*(15-12*x+8*x^2+x^3)/(1-x)^3.
EXAMPLE
a(2)=15 because the Mycielskian of the 1-edge graph is the cycle graph C(5) with Wiener index 5*1+5*2 = 15.
MAPLE
a := proc (n) if n = 2 then 15 else 6*n^2-13*n+18 end if end proc: seq(a(n), n = 2 .. 45);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Aug 27 2013
STATUS
approved