A007411 Number of matrices with n columns whose rows do not cover each other. Also antichain covers of an unlabeled n-set.

1, 4, 19, 179, 16142, 489996794, 1392195548399980209, 789204635842035039135545297410259321

Offset: 2

Author

Micha Hofri (hofri(AT)cs.rice.edu)

Keywords

• nonn
• hard
• more

References

• V. Jovovic and G. Kilibarda, On enumeration of the class of all monotone Boolean functions, in preparation.
• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• M. Hofri, Email to N. J. A. Sloane, May 1994.
• V. Jovovic and G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, in Russian, Diskretnaya Matematika, 11 (1999), no. 4, 127-138.
• V. Jovovic and G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, English translation, in Discrete Mathematics and Applications, 9, (1999), no. 6, 593-605.

Crossrefs

Cf. A037843, A006126, A003182, A006602.

Formula

a(n) = A003182(n) - A003182(n-1) - 1 = A006602(n) - 1.

Extensions

a(7) from A003182. - N. J. A. Sloane, Aug 13 2015

a(8) from A003182. - Bartlomiej Pawelski, Nov 27 2022

a(9) from A003182. - Dmitry I. Ignatov, Nov 27 2023