Number of alternating permutations on 2n letters that avoid a certain pattern of length 5 (see Lewis, 2012, Appendix, for precise definition).
A217821
Number of alternating permutations on 2n letters that avoid a certain pattern of length 5 (see Lewis, 2012, Appendix, for precise definition).
Terms
- a(0) =1a(1) =5a(2) =61a(3) =1194a(4) =30945a(5) =970717a(6) =35033427a(7) =1408275466
External references
- oeis: A217821