Number of permutations of [n] with exactly 3 descents which avoid the pattern 4321.
A095889
Number of permutations of [n] with exactly 3 descents which avoid the pattern 4321.
Terms
- a(0) =10a(1) =148a(2) =1260a(3) =8160a(4) =44790a(5) =220180a(6) =1001000a(7) =4295168a(8) =17633122a(9) =69921460a(10) =269652100a(11) =1016524352a(12) =3760334958a(13) =13690636212a(14) =49172875520a(15) =174559419680a(16) =613383654170
External references
- oeis: A095889