Number of alternating permutations on 2n+1 letters that avoid a certain pattern of length 4 (see Lewis, 2012, Appendix, for precise definition).
A217803
Number of alternating permutations on 2n+1 letters that avoid a certain pattern of length 4 (see Lewis, 2012, Appendix, for precise definition).
Terms
- a(0) =1a(1) =2a(2) =12a(3) =108a(4) =1202a(5) =15234a(6) =210696a(7) =3102296a(8) =47875884
External references
- oeis: A217803