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 1-5 of 5 results.

A001200 Number of linear geometries on n (unlabeled) points.

Original entry on oeis.org

1, 1, 1, 2, 3, 5, 10, 24, 69, 384, 5250, 232929, 28872973
Offset: 0

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Author

N. J. A. Sloane, D.Glynn(AT)math.canterbury.ac.nz

Keywords

Comments

For the labeled case see A056642.
Also a(n) = 1 + number of non-isomorphic simple rank-3 matroids on n elements (see A058731); a(n) = number of non-isomorphic 2-partitions of a set of size n. For 1-partitions see A000041.

References

  • L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 303, #42.
  • CRC Handbook of Combinatorial Designs, 1996, pp. 216, 697.
  • J. Doyen, Sur le nombre d'espaces linéaires non isomorphes de n points. Bull. Soc. Math. Belg. 19 1967 421-437.
  • P. Robillard, On the weighted finite linear spaces. Bull. Soc. Math. Belg. 22 (1970), 227-241.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

A002876 Number of weighted linear spaces of total weight n.

Original entry on oeis.org

1, 2, 4, 8, 16, 36, 85, 239
Offset: 1

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Author

Keywords

References

  • Robillard, Pierre; On the weighted finite linear spaces. Bull. Soc. Math. Belg. 22 (1970), 227-241.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

A002877 Number of connected weighted linear spaces of total weight n.

Original entry on oeis.org

1, 1, 2, 3, 6, 13, 35, 116
Offset: 1

Views

Author

Keywords

References

  • Robillard, Pierre; On the weighted finite linear spaces. Bull. Soc. Math. Belg. 22 (1970), 227-241.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

A309114 Minimal linear spaces on n points.

Original entry on oeis.org

1, 0, 1, 3, 8, 23, 208
Offset: 3

Views

Author

Michael De Vlieger, Jul 13 2019

Keywords

References

  • Batten, Lynn Margaret, and Beutelspacher, Albrecht. The Theory of Finite Linear Spaces: Combinatorics of Points and Lines, Cambridge University Press, 1993.

Crossrefs

A309115 Minimal linear spaces with n nontrivial lines.

Original entry on oeis.org

1, 2, 5, 16
Offset: 1

Views

Author

Michael De Vlieger, Jul 13 2019

Keywords

Comments

Per Haas, a(5) >= 70.

References

  • Batten, Lynn Margaret, and Beutelspacher, Albrecht. The Theory of Finite Linear Spaces: Combinatorics of Points and Lines, Cambridge University Press, 1993.

Crossrefs

Showing 1-5 of 5 results.