A180500 Triangle read by row. T(n,m) gives the number of isomorphism classes of simple arrangements of n pseudolines and m double pseudolines in the projective plane.

1, 1, 1, 1, 1, 1, 1, 2, 4, 13, 1, 5, 48, 626, 6570, 1, 25, 1329, 86715, 4822394, 181403533

Offset: 0

Author

Vincent Pilaud, Sep 08 2010

Keywords

• nonn
• tabl
• more

References

• J. Ferté, V. Pilaud and M. Pocchiola, On the number of arrangements of five double pseudolines, Abstracts 18th Fall Workshop on Comput. Geom. (FWCG08), Troy, NY, October 2008.

Links

• J. Ferté, V. Pilaud and M. Pocchiola, On the number of simple arrangements of five double pseudolines, arXiv:1009.1575 [cs.CG], 2010; Discrete Comput. Geom. 45 (2011), 279-302.

Crossrefs

See A180501 for isomorphism classes of all (not only simple) arrangements of n pseudolines and m double pseudolines in the projective plane.

See A180503 for isomorphism classes of simple arrangements of n pseudolines and m double pseudolines in the Moebius strip.

First diagonal gives A006248.