

A222625


Number of simple connected wellcovered graphs on n nodes.


2



1, 1, 1, 3, 6, 27, 108, 788, 9035, 196928, 7797877, 533938066
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OFFSET

1,4


COMMENTS

A graph is wellcovered if its maximal independent vertex sets are of equal size.


LINKS

F. Hüffner, tinygraph, software for generating integer sequences based on graph properties, version a1db88e


FORMULA



MATHEMATICA

A222626 = {1, 2, 3, 7, 14, 46, 164, 996, 10195, 208168, 8016530, 542165050};
mob[m_, n_] := If[Mod[m, n] == 0, MoebiusMu[m/n], 0];
EULERi[b_] := Module[{a, c, i, d}, c = {}; For[i = 1, i <= Length[b], i++, c = Append[c, i b[[i]]  Sum[c[[d]] b[[i  d]], {d, 1, i  1}]]]; a = {}; For[i = 1, i <= Length[b], i++, a = Append[a, (1/i)*Sum[mob[i, d] c[[d]], {d, 1, i}]]]; Return[a]];


CROSSREFS

Cf. A222626 (number of simple notnecessarily connected wellcovered graphs).
Cf. A287025 (number of simple disconnected wellcovered graphs).


KEYWORD

nonn,more


AUTHOR



EXTENSIONS

a(11)a(12) added using tinygraph by Falk Hüffner, Aug 15 2017


STATUS

approved



