login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A228321 The Wiener index of the graph obtained by applying Mycielski's construction to the path graph on n vertices (n>=2). 1
15, 33, 62, 103, 156, 221, 298, 387, 488, 601, 726, 863, 1012, 1173, 1346, 1531, 1728, 1937, 2158, 2391, 2636, 2893, 3162, 3443, 3736, 4041, 4358, 4687, 5028, 5381, 5746, 6123, 6512, 6913, 7326, 7751, 8188, 8637, 9098, 9571, 10056, 10553, 11062 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

REFERENCES

D. B. West, Introduction to Graph Theory, 2nd ed., Prentice-Hall, NJ, 2001, p. 205.

LINKS

Table of n, a(n) for n=2..44.

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).

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

Sequence in context: A020184 A231371 A228318 * A277385 A108517 A211327

Adjacent sequences:  A228318 A228319 A228320 * A228322 A228323 A228324

KEYWORD

nonn,easy

AUTHOR

Emeric Deutsch, Aug 27 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 26 05:50 EDT 2019. Contains 326330 sequences. (Running on oeis4.)