A141824 Antidiagonals of table A047888 (which counts longest increasing subsequences and pattern avoidances).

1, 2, 4, 9, 24, 75, 269, 1095, 5039, 26084, 150356, 952526, 6553011, 48553418, 385693800, 3277413802, 29741002168, 287555932433, 2952769116993, 32079033571080, 367336668735826, 4419518218479215, 55733223965845539, 735448682261126767, 10142738983005750681

Offset

1,2

Comments

Note that:

A000108 avoids string "123"

A005808 avoids string "1234"

A047889 avoids string "12345"

Note also that the left half and central diagonal of A047888 are partial sums of table A047874.

Links

Table of n, a(n) for n=1..25.

Example

We can write A141824(n) = 1 2 4 9 24 ... because A047888 begins
  1;
  1,  1;
  1,  2,  1;
  1,  5,  2,  1;
  1, 14,  6,  2,  1;
etc.

Crossrefs

Cf. A000108 (Catalan numbers), A005808, A047889, A047874.

Sequence in context: A236756 A291378 A125654 * A005001 A091151 A093542

Adjacent sequences: A141821 A141822 A141823 * A141825 A141826 A141827

Keyword

nonn

Author

Alford Arnold, Jul 08 2008

Extensions

a(12)-a(25) from Alois P. Heinz, Apr 10 2012

Status

approved