A005020 The number of n X n (0,1)-matrices with a 1-width of 2. (Formerly M2182)

0, 2, 168, 32738, 20825760, 47942081642

Offset

1,2

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

Table of n, a(n) for n=1..6.

Sean A. Irvine, Java program (github)

Index entries for sequences related to binary matrices

Crossrefs

Sequence in context: A297407 A142602 A200042 * A157316 A007760 A230511

Adjacent sequences: A005017 A005018 A005019 * A005021 A005022 A005023

Keyword

nonn

Author

N. J. A. Sloane

Extensions

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

Status

approved