A046082 Number of ultraconnected graphs on n unlabeled nodes.

1, 1, 1, 2, 4, 19, 139, 2319, 77423, 4909331, 554491273

Offset: 1

Author

Jason Grout (grout(AT)math.byu.edu), May 07 2003

Keywords

• hard
• nonn

Comments

The ultraconnected graphs are related to the positive definite matrix completion problem.

Links

• W. W. Barrett, C. R. Johnson and R. Loewy, Critical graphs for the positive definite completion problem., SIAM J. Matrix Anal. Appl., Vol. 20 (1999), no. 1, 117-130.

Extensions

Broken link fixed by M. F. Hasler, Apr 05 2015