A005336 Number of labeled nonseparable (or 2-connected) bipartite graphs with 2n nodes.

1, 3, 355, 297619, 1120452771, 15350524923547, 738416821509929731, 126430202628042630866787, 78847417416749666369637926851, 183373380693566591129149674727445419, 1623847327688450079238401833083018045926051, 55669578575421273854874611540671620662810228887603

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Comments

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.

Crossrefs

Bisection of A004100.

Cf. A005334, A005335 (each part with n nodes).

Extensions

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