cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A056642 Number of linear spaces on n (labeled) points.

Original entry on oeis.org

1, 1, 2, 6, 32, 353, 8390, 433039, 50166354, 13480967630
Offset: 1

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Author

W. M. B. Dukes (dukes(AT)stp.dias.ie), Aug 28 2000

Keywords

Comments

Alternatively, number of linear geometries on n (labeled) points. For the unlabeled case see A001200.
Also a(n) = 1 + number of simple rank-3 matroids on n (labeled) elements; a(n) = number of 2-partitions of a set of size n.

References

  • L. M. Batten and A. Beutelspacher: The theory of finite linear spaces, Cambridge Univ. Press, 1993 (see the Appendix).
  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 303, #42.
  • J. Doyen, Sur le nombre d'espaces linĂ©aires non isomorphes de n points, Bull. Soc. Math. Belg. 19 (1967), 421-437.
  • J. A. Thas, Sur le nombre d'espaces linĂ©aires non isomorphes de n points, Bull. Soc. Math. Belg. 21 (1969), 57-66.

Crossrefs

Corrected version of A001199. Cf. A002773, A001200, A031436, A058731.

Extensions

a(9) and a(10) from Gordon Royle, May 29 2006

A031437 Number of nonisomorphic regular linear spaces RLIN(n).

Original entry on oeis.org

1, 1, 1, 2, 2, 2, 4, 3, 4, 9, 14, 33, 839, 2041, 22192
Offset: 0

Views

Author

Anton Betten (Anton.Betten(AT)uni-bayreuth.de)

Keywords

References

  • A. Betten and D. Betten: Regular Linear Spaces, Beitraege Algebra Geometrie 38 (1): 111-124, 1997.
  • A. Betten and D. Betten: The proper linear spaces on 17 points, Discrete Applied Mathematics, Volume 95, no. 1-3, 1999, pp. 83-108.
  • CRC Handbook of Combinatorial Designs, in the article by Gronau, Mullin and Pietsch.

Crossrefs

A001439 Number of proper linear spaces of order n.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 1, 1, 1, 3, 7, 1, 120, 398
Offset: 3

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Author

Keywords

References

  • CRC Handbook of Combinatorial Designs, 1996, p. 216.

Crossrefs

Probably an erroneous version of A031436.

A031438 Number of nonisomorphic proper regular linear spaces, PRLIN(n).

Original entry on oeis.org

1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 3, 3, 0, 84, 25, 0
Offset: 0

Views

Author

Anton Betten (Anton.Betten(AT)uni-bayreuth.de)

Keywords

References

  • A. Betten and D. Betten: The proper linear spaces on 17 points, Discrete Applied Mathematics, Volume 95, no. 1-3, 1999, pp. 83-108.

Crossrefs

Showing 1-4 of 4 results.