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A180503 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 Moebius strip. 2
1, 1, 1, 1, 1, 1, 1, 3, 7, 16, 2, 13, 140, 1499, 11502, 3, 122, 5589, 245222, 9186477, 238834187 (list; table; graph; refs; listen; history; text; internal format)
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..20.

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 A180502 for isomorphism classes of all (not only simple) arrangements of n pseudolines and m double pseudolines in the Moebius strip.

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

First diagonal gives A006247.

Sequence in context: A206851 A033089 A175878 * A153578 A018852 A260465

Adjacent sequences:  A180500 A180501 A180502 * A180504 A180505 A180506

KEYWORD

nonn,tabl,more

AUTHOR

Vincent Pilaud, Sep 08 2010

STATUS

approved

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Last modified May 11 21:35 EDT 2021. Contains 343808 sequences. (Running on oeis4.)