A048873 - OEIS

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A048873

Number of non-isomorphic arrangements of n lines in the real projective plane such that the lines do not pass through a common point and no point belongs to more than 2 lines.

1, 1, 1, 4, 11 (list; graph; refs; listen; history; internal format)

	OFFSET	`3,4`
	COMMENTS	`These are called simple arrangements.`
	REFERENCES	`J. E. Goodman and J. O'Rourke, editors, Handbook of Discrete and Computational Geometry, CRC Press, 1997, p. 102.` `B. Gr\"{u}nbaum, Arrangements and Spreads. American Mathematical Society, Providence, RI, 1972, p. 6.`
	CROSSREFS	`Cf. A003036, A048872.` `Sequence in context: A102958 A085649 A152396 * A091390 A132150 A091389` `Adjacent sequences: A048870 A048871 A048872 * A048874 A048875 A048876`
	KEYWORD	`nonn,nice,more`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`
	EXTENSIONS	`The next term is conjectured to be 135.`

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Last modified February 16 21:51 EST 2012. Contains 205978 sequences.