A131649 - OEIS

A131649

Number of distinct improper 2-coloring of edges for odd-order cyclic graphs.

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

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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: A291441 A331967 A301147 * 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