From descending subsequences of permutations.
A006220
From descending subsequences of permutations.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =10a(4) =45a(5) =251a(6) =1638a(7) =12300a(8) =104877a(9) =1000135a(10) =10534062a(11) =121436206a(12) =1521332904
External references
- oeis: A006220