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

 

Logo

The submissions stack has been unacceptably high for several months now. Please voluntarily restrict your submissions and please help with the editing. (We don't want to have to impose further limits.)

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 | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified August 29 01:49 EDT 2015. Contains 261184 sequences.