A001437 Number of connected graphs with n nodes and ceiling(n(n-1)/4) edges.

1, 1, 2, 5, 22, 138, 1579, 33366, 1348674, 105925685, 15968704512, 4520384306832, 2402814904220039, 2425664021535713098, 4647586298937784001491, 16787189663016572148130262, 114716901953374968257425111039

Offset: 2

Author

N. J. A. Sloane

Keywords

• nonn
• nice

References

• N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Sean A. Irvine, Table of n, a(n) for n = 2..40
• M. L. Stein and P. R. Stein, Enumeration of Linear Graphs and Connected Linear Graphs up to p = 18 Points. Report LA-3775, Los Alamos Scientific Laboratory of the University of California, Los Alamos, NM, Oct 1967.

Crossrefs

Largest entries in the rows of the table in A054924.

Extensions

More terms from Sean A. Irvine, Jul 24 2012