A344019 A tight upper bound on the order of a finite subgroup of the collineation group of the free projective plane F_n.

24, 12, 120, 240, 1440, 10080, 80640, 725760, 7257600, 79833600, 958003200, 12454041600, 174356582400, 2615348736000, 41845579776000, 711374856192000, 12804747411456000, 243290200817664000, 4865804016353280000, 102181884343418880000, 2248001455555215360000, 51704033477769953280000, 1240896803466478878720000

Offset

4,1

Links

Table of n, a(n) for n=4..26.

Oddvar Iden and Jan G. Moe, Automorphism groups of free Moebius planes and free Laguerre planes, Geometriae dedicata 7.2 (1978): 209-222.

Formula

Equals 2*(n-2)! for n = 5 and n >= 7.

E.g.f.: x*(60 - 30*x - 10*x^2 + 25*x^3 + 3*x^5)/30 + 2*(1 - x)*log(1 - x). - Stefano Spezia, Jun 21 2021

Crossrefs

Sequence in context: A040555 A081314 A119872 * A002550 A075605 A334219

Adjacent sequences: A344016 A344017 A344018 * A344020 A344021 A344022

Keyword

nonn

Author

N. J. A. Sloane, Jun 21 2021

Status

approved