A005334 - OEIS

A005334

Number of labeled nonseparable (or 2-connected) bicolored graphs with n nodes of the first color and n nodes of the second color.
(Formerly M5244)

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

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.

Sequence in context: A292750 A199837 A267916 * A033511 A246240 A273352

Adjacent sequences: A005331 A005332 A005333 * A005335 A005336 A005337

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

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

STATUS

approved