A210669 Number of equivalence classes of S_n under transformations of positionally adjacent elements of the form abc <--> acb <--> cba where a

1, 1, 2, 4, 8, 14, 27, 68, 159, 496

Offset: 0

Author

Tom Roby, May 08 2012

Keywords

• nonn

Comments

Also number of equivalence classes of S_n under transformations of positionally adjacent elements of the form abc <--> bac <--> cba where a

Examples

			From _Alois P. Heinz_, May 19 2012: (Start)
a(3) = 4: {123, 132, 321}, {213}, {231}, {312}.
a(4) = 8: {1234, 1243, 1324, 1342, 1423, 1432, 3214, 4213, 4312}, {2134, 2143, 2341, 2431, 4123, 4132, 4321}, {2314}, {2413}, {3124, 3142, 3421}, {3241}, {3412}, {4231}. (End)
		

Links

• Steven Linton, James Propp, Tom Roby, and Julian West, Equivalence classes of permutations under various relations generated by constrained transpositions, 2011 arXiv:1111.3920 [math.CO], J. Int. Seq. 15 (2012) #12.9.1

Crossrefs

Cf. A210667, A210668, A210671, A212417, A212418.

Extensions

Definition improved and comment added by Tom Roby, May 15 2012

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.