Number of permutations p of [n] such that p(i) > p(i+1) iff i == 2 (mod 3).
A249583
Number of permutations p of [n] such that p(i) > p(i+1) iff i == 2 (mod 3).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =5a(5) =9a(6) =40a(7) =169a(8) =477a(9) =3194a(10) =19241a(11) =74601a(12) =666160a(13) =5216485a(14) =25740261a(15) =287316122a(16) =2769073949a(17) =16591655817a(18) =222237912664
External references
- oeis: A249583