This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A048873 #9 Dec 12 2014 10:39:38 %S A048873 1,1,1,4,11 %N 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. %C A048873 These are called simple arrangements. %D A048873 J. E. Goodman and J. O'Rourke, editors, Handbook of Discrete and Computational Geometry, CRC Press, 1997, p. 102. %D A048873 B. Grünbaum, Arrangements and Spreads. American Mathematical Society, Providence, RI, 1972, p. 6. %Y A048873 Cf. A003036, A048872. %K A048873 nonn,nice,more %O A048873 3,4 %A A048873 _N. J. A. Sloane_ %E A048873 The next term is conjectured to be 135.