A160047 Denominator of the Harary number for the cycle graph C_n.

1, 1, 1, 1, 2, 1, 6, 3, 4, 6, 60, 5, 20, 10, 28, 35, 280, 140, 2520, 126, 120, 1260, 27720, 1155, 5544, 13860, 40040, 12870, 360360, 12012, 360360, 45045, 21840, 360360, 350064, 340340, 4084080, 2042040, 1989680, 1939938, 15519504, 369512, 5173168

Offset

1,5

Comments

Extended to a(1)-a(2) using the formula.

Links

Table of n, a(n) for n=1..43.

Eric Weisstein's World of Mathematics, Harary Index

Example

0, 1, 3, 5, 15/2, 10, 77/6, 47/3, 75/4, 131/6, ...

Mathematica

Denominator[Table[1 - Mod[n, 2] + n HarmonicNumber[Floor[(n - 1)/2]], {n, 43}]] (* Eric W. Weisstein, Dec 06 2017 *)

Crossrefs

Cf. A160046.

Sequence in context: A350684 A124443 A077172 * A249990 A097288 A223894

Adjacent sequences: A160044 A160045 A160046 * A160048 A160049 A160050

Keyword

nonn

Author

Eric W. Weisstein, Apr 30 2009

Status

approved