

A244020


Number of new points at the nth step of the following iteration, starting with four points in general position in the real projective plane: dualize the current pointset to a family of lines, take all intersections of those lines, repeat.


8




OFFSET

1,1


COMMENTS

A140468 is the main sequence for this problem. We have a(n) = b(n)b(n2), where b(n) = A140468(n).


LINKS

Table of n, a(n) for n=1..9.
Joshua Cooper, Mark Walters, Iterated pointline configurations grow doublyexponentially, Discrete Comput. Geom. 43 (2010), no. 3, 554562. MR2587837 (2011f:51016) 51M04 (52C35).
Shalosh B. Ekhad, Doron Zeilberger, Enumerative Geometrical Genealogy (Or: The Sex Life of Points and Lines), arXiv:1406.5157 [math.CO], (19June2014)


CROSSREFS

Related sequences: A140468, A244020A244026.
Sequence in context: A213080 A200365 A198121 * A179374 A081709 A200640
Adjacent sequences: A244017 A244018 A244019 * A244021 A244022 A244023


KEYWORD

nonn,more


AUTHOR

N. J. A. Sloane, Jun 20 2014


STATUS

approved



