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URL: https://oeis.org/A180501

⇱ A180501 - OEIS

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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.
2
1, 1, 1, 1, 1, 1, 1, 3, 9, 46, 2, 16, 265, 6998, 153528
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
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 * A382230 A188678 A107090
KEYWORD
nonn,tabl,more
AUTHOR
Vincent Pilaud, Sep 08 2010
STATUS
approved