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 A165655 Number of disconnected 5-regular (quintic) graphs on 2n vertices. 12
 0, 0, 0, 0, 0, 0, 1, 3, 66, 8029, 3484760, 2595985770, 2815099031417, 4230059694039460, 8529853839173455678, 22496718465713456081402, 75951258300080722467845995, 322269241532759484921710401976 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,8 LINKS N. J. A. Sloane, Transforms Jason Kimberley, Disconnected regular graphs (with girth at least 3) Eric Weisstein's World of Mathematics, Disconnected Graph Eric Weisstein's World of Mathematics, Quintic Graph FORMULA a = A165626 - A006821 = Euler_transformation(A006821) - A006821. a(n)=A068933(2n,5). CROSSREFS 5-regular simple graphs: A006821 (connected), this sequence (disconnected), A165626 (not necessarily connected). Disconnected regular simple graphs: A068932 (any degree), A068933 (triangular array), specified degree k: A165652 (k=2), A165653 (k=3), A033483 (k=4), this sequence (k=5), A165656 (k=6), A165877 (k=7), A165878 (k=8), A185293 (k=9), A185203 (k=10), A185213 (k=11). Sequence in context: A187547 A157554 A185053 * A157576 A105443 A065425 Adjacent sequences:  A165652 A165653 A165654 * A165656 A165657 A165658 KEYWORD nonn,hard,more AUTHOR Jason Kimberley, Sep 28 2009 EXTENSIONS Terms a(13)-a(17), due to the extension of A006821 by Andrew Howroyd, from Jason Kimberley, Mar 12 2020 STATUS approved

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Last modified September 26 16:43 EDT 2020. Contains 337374 sequences. (Running on oeis4.)