A006220 From descending subsequences of permutations. (Formerly M2866)

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

Offset

1,3

References

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

Links

Table of n, a(n) for n=1..13.

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

Crossrefs

Diagonal of A224652.

Sequence in context: A330250 A207652 A099237 * A020026 A077002 A268224

Adjacent sequences: A006217 A006218 A006219 * A006221 A006222 A006223

Keyword

nonn,more

Author

N. J. A. Sloane.

Extensions

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

Status

approved