All permutations of a sequence

*To*: mathgroup at smc.vnet.net*Subject*: [mg76158] All permutations of a sequence*From*: Virgil Stokes <vs at it.uu.se>*Date*: Thu, 17 May 2007 05:52:31 -0400 (EDT)

I would like to get all unique permutations of a sequence (e.g. {1,2,3,4,5,6,7,8,9,10,11,12,13}) with the constraint that all sequences that have an opposite ordering are not included (e.g. {13, 12, 11,10,9,8,6,5,4,3,2,1}) would not be included. Are there some Mathematica commands that can be used to efficiently generate these permutations? --V. Stokes