A054917 - OEIS

%I #20 Aug 27 2019 04:21:54

%S 1,0,0,0,1,2,2,6,5,14,6,54,12,46,40,258,34,350,58,1166,230,798,186,

%T 15338,458,4206,1416,25734,1180,46164,2190,676830,6750,132506,11138,

%U 1962310,14600,814094,48432,13101722,52486,9461632,99878,39133004,399310,34333422,364722

%N Number of connected unlabeled vertex-transitive graphs with n nodes such that complement is also connected.

%H V. A. Liskovets, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL3/LISK/Derseq.html">Some easily derivable sequences</a>, J. Integer Sequences, 3 (2000), #00.2.2.

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

%t nmax = 47;

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

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

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

%t Array[a, nmax] (* _Jean-François Alcover_, Aug 27 2019, after _Andrew Howroyd_ *)

%Y Cf. A006799, A006800.

%K nonn

%O 1,6

%A _N. J. A. Sloane_, May 24 2000

%E Missing a(1) inserted and a(32)-a(47) from _Andrew Howroyd_, Nov 27 2018