A087145 Number of distinct disconnected simple symmetric graphs on n nodes.

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

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{d|n, 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: A338899 A362071 A194943 * A117172 A029207 A111902

Adjacent sequences: A087142 A087143 A087144 * A087146 A087147 A087148

Keyword

nonn,more

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