A290344 Denominators of the Kirchhoff (and Harary) index for the n-hypercube graph.

1, 1, 1, 3, 3, 15, 15, 105, 105, 315, 63, 693, 693, 9009, 9009, 45045, 45045, 765765, 765765, 14549535, 14549535, 14549535, 14549535, 334639305, 334639305, 1673196525, 1673196525, 5019589575, 5019589575, 145568097675, 145568097675, 4512611027925, 4512611027925

Offset

0,4

Links

Table of n, a(n) for n=0..32.

Eric Weisstein's World of Mathematics, Harary Index

Eric Weisstein's World of Mathematics, Hypercube Graph

Eric Weisstein's World of Mathematics, Kirchhoff Index

Example

Kirchhoff (and Harary) indices are 0, 1, 5, 58/3, 206/3, 3548/15, 12136/15, 291824/105, 1012048/105, ....

Mathematica

Table[-2^(n - 1) HarmonicNumber[n] - 4^n Re[LerchPhi[2, 1, n + 1]], {n, 0, 32}] // Denominator
Table[2^(-1 + n) n HypergeometricPFQ[{1, 1, 1 - n}, {2, 2}, -1], {n, 0, 32}] // Denominator (* Eric W. Weisstein, Dec 11 2017 *)

Crossrefs

Cf. A290343 (numerators).

Sequence in context: A100735 A362531 A129356 * A217858 A185275 A055634

Adjacent sequences: A290341 A290342 A290343 * A290345 A290346 A290347

Keyword

nonn,frac

Author

Eric W. Weisstein, Jul 28 2017

Status

approved