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A132346 Number of nonisomorphic arrangements of n lines in the real projective plane, including the arrangement where all the lines pass through a common point. 3
1, 1, 1, 2, 3, 5, 18 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

See the illustration of initial terms in A048872.

REFERENCES

J. E. Goodman and J. O'Rourke, editors, Handbook of Discrete and Computational Geometry, CRC Press, 1997, p. 102.

B. Gr├╝nbaum, Arrangements and Spreads. American Mathematical Society, Providence, RI, 1972, p. 4.

LINKS

Table of n, a(n) for n=0..6.

CROSSREFS

Equals A048872 + 1. Cf. A003036, A048873. Different from A121510.

Sequence in context: A004249 A268210 A121510 * A284530 A041293 A041713

Adjacent sequences:  A132343 A132344 A132345 * A132347 A132348 A132349

KEYWORD

nonn,nice,more

AUTHOR

N. J. A. Sloane, Nov 09 2007

STATUS

approved

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Last modified December 15 22:02 EST 2019. Contains 330012 sequences. (Running on oeis4.)