A180501 - OEIS

A180501

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

1, 1, 1, 1, 1, 1, 1, 3, 9, 46, 2, 16, 265, 6998, 153528

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OFFSET

0,8

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

Table of n, a(n) for n=0..14.

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 A180500 for isomorphism classes of simple arrangements of n pseudolines and m double pseudolines in the projective plane.

See A180502 for isomorphism classes of arrangements of n pseudolines and m double pseudolines in the Moebius strip.

First diagonal gives A063800.

Sequence in context: A013492 A106341 A065407 * A188678 A107090 A190625

Adjacent sequences: A180498 A180499 A180500 * A180502 A180503 A180504

KEYWORD

nonn,tabl,more

AUTHOR

Vincent Pilaud, Sep 08 2010

STATUS

approved