Number of permutations of (1,...,n) having n-6 inversions (n>=6).
A005284
Number of permutations of (1,...,n) having n-6 inversions (n>=6).
Terms
- a(0) =1a(1) =6a(2) =27a(3) =111a(4) =440a(5) =1717a(6) =6655a(7) =25728a(8) =99412a(9) =384320a(10) =1487262a(11) =5762643a(12) =22357907a(13) =86859412a(14) =337879565a(15) =1315952428a(16) =5131231668a(17) =20029728894a(18) =78265410550a(19) =306109412100
External references
- oeis: A005284