Number of alternating permutations on 2n letters that avoid a certain pattern of length 4 (see Lewis, 2012, Appendix, for precise definition).
A217811
Number of alternating permutations on 2n letters that avoid a certain pattern of length 4 (see Lewis, 2012, Appendix, for precise definition).
Terms
- a(0) =1a(1) =5a(2) =61a(3) =744a(4) =10329a(5) =157586a(6) =2581722a(7) =44710952a(8) =809508414
External references
- oeis: A217811