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A054917 Number of connected unlabeled vertex-transitive graphs with n nodes such that complement is also connected. 0
1, 0, 0, 0, 1, 2, 2, 6, 5, 14, 6, 54, 12, 46, 40, 258, 34, 350, 58, 1166, 230, 798, 186, 15338, 458, 4206, 1416, 25734, 1180, 46164, 2190, 676830, 6750, 132506, 11138, 1962310, 14600, 814094, 48432, 13101722, 52486, 9461632, 99878, 39133004, 399310, 34333422, 364722 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..47.

V. A. Liskovets, Some easily derivable sequences, J. Integer Sequences, 3 (2000), #00.2.2.

FORMULA

a(n) = 2*A006800(n) - A006799(n).

MATHEMATICA

nmax = 47;

A006799 = Cases[Import["https://oeis.org/A006799/b006799.txt", "Table"], {_, _}][[All, 2]];

A006800 = Table[Sum[MoebiusMu[n/d] A006799[[d]], {d, Divisors[n]}], {n, 1, nmax}];

a[n_] := 2*A006800[[n]] - A006799[[n]];

Array[a, nmax] (* Jean-Fran├žois Alcover, Aug 27 2019, after Andrew Howroyd *)

CROSSREFS

Cf. A006799, A006800.

Sequence in context: A286278 A156563 A201500 * A111419 A306768 A174399

Adjacent sequences:  A054914 A054915 A054916 * A054918 A054919 A054920

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, May 24 2000

EXTENSIONS

Missing a(1) inserted and a(32)-a(47) from Andrew Howroyd, Nov 27 2018

STATUS

approved

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Last modified June 6 14:04 EDT 2020. Contains 334827 sequences. (Running on oeis4.)