

A052446


Number of unlabeled simple connected bridged graphs on n nodes.


25



0, 1, 1, 3, 10, 52, 351, 3714, 63638, 1912203, 103882478, 10338614868, 1892863194064, 639799762452639, 400857034314325045, 467526363203064793081, 1019286659457016864347582, 4170114225096278323394128049, 32130213534058019378134295287305
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OFFSET

1,4


COMMENTS

These are unlabeled connected graphs with spanning edgeconnectivity 1, where the spanning edgeconnectivity of a graph is the minimum number of edges that must be removed (without removing incident vertices) to obtain a disconnected or empty graph.  Gus Wiseman, Sep 02 2019


LINKS



FORMULA



MATHEMATICA

A001349 = Cases[Import["https://oeis.org/A001349/b001349.txt", "Table"], {_, _}][[All, 2]];
A007146 = Cases[Import["https://oeis.org/A007146/b007146.txt", "Table"], {_, _}][[All, 2]] ;


CROSSREFS

Cf. A001349 (number of simple connected graphs).
Cf. A007146 (number of simple connected bridgeless graphs).
Cf. A263914 (number of simple bridgeless graphs).
Cf. A263915 (number of simple bridged graphs).
Row sums of A327077 if the first column is removed.
BIInumbers of setsystems with spanning edgeconnectivity 1 are A327111.


KEYWORD

nonn,hard


AUTHOR



EXTENSIONS



STATUS

approved



