

A087145


Number of distinct disconnected simple symmetric graphs on n nodes.


2



0, 1, 1, 2, 1, 3, 1, 4, 2, 4, 1, 9, 1, 4, 4, 9, 1, 11, 1, 14, 4, 4, 1, 25, 3, 6, 6, 14, 1, 27, 1
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OFFSET

1,4


LINKS

Table of n, a(n) for n=1..31.
Eric Weisstein's World of Mathematics, Symmetric Graph


FORMULA

a(n) = Sum{dn, d<n} A133181(d).  Charlie Neder, Apr 24 2019


CROSSREFS

Cf. A133181 (number of connected symmetric graphs).
Cf. A286931 (number of not necessarily connected symmetric graphs).
Sequence in context: A211110 A200780 A194943 * A117172 A029207 A111902
Adjacent sequences: A087142 A087143 A087144 * A087146 A087147 A087148


KEYWORD

nonn,more,changed


AUTHOR

Eric W. Weisstein, Aug 19 2003


EXTENSIONS

Corrected and extended by David Wasserman, Feb 14 2006
a(12)a(31) from Charlie Neder, Apr 24 2019


STATUS

approved



