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A160046 Numerator of the Harary number for the cycle graph C_n. 1
0, 1, 3, 5, 15, 10, 77, 47, 75, 131, 1507, 142, 637, 353, 1089, 1487, 12937, 6989, 135451, 7255, 7381, 82451, 1925353, 84866, 430105, 1132133, 3437979, 1158863, 33980257, 1183745, 37068467, 4828073, 2436559, 41781863, 42142223, 42482563 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

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

LINKS

Table of n, a(n) for n=1..36.

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

Numerator[Table[1 - Mod[n, 2] + n HarmonicNumber[Floor[(n - 1)/2]], {n, 20}]] (* Eric W. Weisstein, Dec 06 2017 *)

CROSSREFS

Cf. A160047.

Sequence in context: A180620 A332382 A277323 * A272024 A111869 A093015

Adjacent sequences:  A160043 A160044 A160045 * A160047 A160048 A160049

KEYWORD

nonn

AUTHOR

Eric W. Weisstein, Apr 30 2009

STATUS

approved

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Last modified May 26 02:56 EDT 2020. Contains 334613 sequences. (Running on oeis4.)