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

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A131649 Number of distinct improper 2-coloring of edges for odd-order cyclic graphs. 0
4, 8, 16, 32, 54, 82, 116, 156, 202, 254, 312, 376, 446, 522, 604, 692, 786, 886, 992, 1104, 1222, 1346, 1476, 1612, 1754, 1902, 2056, 2216, 2382, 2554, 2732, 2916, 3106, 3302, 3504, 3712, 3926, 4146, 4372, 4604, 4842, 5086, 5336, 5592, 5854 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

LINKS

Table of n, a(n) for n=3..47.

Index entries for sequences related to colorings

FORMULA

Conjectured g.f.: 4 + (2*x*((x-2)^2*x-4))/(x-1)^3. - Harvey P. Dale, Jul 07 2013

For n>4, a(n) = 3*n^2 - 17*n + 26 (conjectured). - Ralf Stephan, Jul 08 2013

MATHEMATICA

Table[If[n == 3, n + 1, If[n == 5, n + 3, 1/2 (13 - 5 n) + 3/4 (-1 + n)^2]], {n, 3, 31, 2}]

Join[{4, 8}, Table[(13-5n)/2+(3(n-1)^2)/4, {n, 7, 91, 2}]] (* Harvey P. Dale, Jul 07 2013 *)

CROSSREFS

Sequence in context: A101434 A048168 A175341 * A003199 A189925 A007096

Adjacent sequences:  A131646 A131647 A131648 * A131650 A131651 A131652

KEYWORD

nonn

AUTHOR

M. Razid Black (mrazidblack(AT)hotmail.com), Sep 10 2007

EXTENSIONS

More terms from Harvey P. Dale, Jul 07 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 10 13:38 EST 2016. Contains 279004 sequences.