

A007146


Number of simple connected bridgeless graphs with n nodes.
(Formerly M2909)


8



1, 0, 1, 3, 11, 60, 502, 7403, 197442, 9804368, 902818087, 153721215608, 48443044675155, 28363687700395422, 30996524108446916915, 63502033750022111383196, 244852545022627009655180986
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OFFSET

1,4


REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

R. J. Mathar, Table of n, a(n) for n = 1..22
P. Hanlon and R. W. Robinson, Counting bridgeless graphs, J. Combin. Theory, B 33 (1982), 276305, Table III.
Eric Weisstein's World of Mathematics, Bridgeless Graph
Eric Weisstein's World of Mathematics, Connected Graph
Eric Weisstein's World of Mathematics, Simple Graph


FORMULA

a(n) = A005470(n)  A263914(n).


CROSSREFS

Cf. A005470 (number of simple graphs).
Cf. A007145.
Cf. A052446 (number of simple connected bridged graphs).
Cf. A263914 (number of simple bridgeless graphs).
Cf. A263915 (number of simple bridged graphs).
Sequence in context: A136440 A303871 A231344 * A076475 A125556 A127516
Adjacent sequences: A007143 A007144 A007145 * A007147 A007148 A007149


KEYWORD

nonn,nice,easy


AUTHOR

N. J. A. Sloane


EXTENSIONS

Reference gives first 22 terms.


STATUS

approved



