A005020 The number of n X n (0,1)-matrices with a 1-width of 2.

0, 2, 168, 32738, 20825760, 47942081642

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Comments

Determining the 1-width of a matrix is NP-complete. - Sean A. Irvine, Mar 06 2020

References

• Lam, Clement W. H. The distribution of 1-widths of (0, 1)-matrices. Discrete Math. 20 (1977/78), no. 2, 109-122.
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Sean A. Irvine, Java program (github)
• Index entries for sequences related to binary matrices

Extensions

a(1) corrected and title improved by Sean A. Irvine, Mar 06 2020