A006220 From descending subsequences of permutations.

1, 1, 3, 10, 45, 251, 1638, 12300, 104877, 1000135, 10534062, 121436206, 1521332904

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• more

References

• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• S. Pilpel, Descending subsequences of random permutations, J. Combin. Theory, A 53 (1990), 96-116.

Crossrefs

Diagonal of A224652.

Extensions

a(11)-a(13) from Sean A. Irvine, Feb 03 2017