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

Offset: 3

Author

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

Keywords

• nonn

Links

• Index entries for sequences related to colorings

Programs

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 *)

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

Extensions

More terms from Harvey P. Dale, Jul 07 2013