A005334 Number of labeled nonseparable (or 2-connected) bicolored graphs with n nodes of the first color and n nodes of the second color.

1, 1, 34, 7037, 6317926, 21073662977, 251973418941994, 10878710974408306717, 1727230695707098000548430, 1028983422758641650604161840065, 2342608062302306704492272616530549874, 20683716767972841770515007707311751484424893

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Comments

The two color classes are not interchangeable and have separate labels. Nonseparable graphs are also called blocks.

References

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

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..50
• F. Harary and R. W. Robinson, Labeled bipartite blocks, Canad. J. Math., 31 (1979), 60-68.
• F. Harary and R. W. Robinson, Labeled bipartite blocks, Canad. J. Math., 31 (1979), 60-68. (Annotated scanned copy)

Crossrefs

Main diagonal of A123301 as an array.

Cf. A005333, A005335, A005336.

Extensions

Name clarified and more terms added by Andrew Howroyd, Jan 03 2021