A005643 Number of labeled irreducible 2-connected graphs with n edges. (Formerly M5191)

1, 26, 1858, 236856, 53458832, 21494404400, 15580475076986, 20666605559464968, 50987322515860980236, 237747564913232367202656, 2125708395579372100915553094

Offset

4,2

References

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

Links

Table of n, a(n) for n=4..14.

T. R. S. Walsh, Counting labeled three-connected and homeomorphically irreducible two-connected graphs, J. Combin. Theory Ser. B 32 (1982), no. 1, 1-11.

Crossrefs

Cf. A054597.

Sequence in context: A123537 A220503 A054597 * A054853 A257947 A245929

Adjacent sequences: A005640 A005641 A005642 * A005644 A005645 A005646

Keyword

nonn

Author

N. J. A. Sloane.

Status

approved