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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.
5

%I #9 Dec 12 2014 10:39:38

%S 1,1,1,4,11

%N 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.

%C These are called simple arrangements.

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

%D B. Grünbaum, Arrangements and Spreads. American Mathematical Society, Providence, RI, 1972, p. 6.

%Y Cf. A003036, A048872.

%K nonn,nice,more

%O 3,4

%A _N. J. A. Sloane_

%E The next term is conjectured to be 135.