%N Number of isomorphism classes of unstretchable simplicial arrangements of n pseudolines in the real projective plane that satisfy Pappus's theorem.
%C Near-pencil arrangements are excluded.
%H M. Cuntz, <a href="https://arxiv.org/abs/1108.3000">Simplicial Arrangements with up to 27 Lines</a>, arXiv:1108.3000 [math.CO], 2011.
%H M. Cuntz, <a href="https://doi.org/10.1007/s00454-012-9423-7">Simplicial Arrangements with up to 27 Lines</a>, Discrete Comput. Geom. 48 (2012), no. 3, 682--701. MR2957638.
%Y Cf. A216036, A216037.
%A _N. J. A. Sloane_, Aug 30 2012