OFFSET
0,6
LINKS
Jason Kimberley, Disconnected regular graphs (with girth at least 3)
Jason Kimberley, Index of sequences counting disconnected k-regular simple graphs with girth at least g
Eric Weisstein's World of Mathematics, Cubic Graph
Eric Weisstein's World of Mathematics, Disconnected Graph
MATHEMATICA
A[s_Integer] := With[{s6 = StringPadLeft[ToString[s], 6, "0"]}, Cases[ Import["https://oeis.org/A" <> s6 <> "/b" <> s6 <> ".txt", "Table"], {_, _}][[All, 2]]];
A005638 = A@005638;
A002851 = A@002851;
a /@ Range[0, 20] (* Jean-François Alcover, Jan 21 2020 *)
CROSSREFS
3-regular simple graphs: A002851 (connected), this sequence (disconnected), A005638 (not necessarily connected).
KEYWORD
nonn,hard
AUTHOR
Jason Kimberley, Sep 28 2009
STATUS
approved