A318532 Number of finite sets of set partitions of {1,...,n} such that any two have meet {{1},...,{n}} and join {{1,...,n}}.

2, 4, 11, 51, 635, 15591

Offset

1,1

Links

Table of n, a(n) for n=1..6.

Example

The a(3) = 11 sets of set partitions:
        0
    {{1,2,3}}
   {{1,3},{2}}
   {{1,2},{3}}
   {{1},{2,3}}
  {{1},{2},{3}}
   {{1,2},{3}}   {{1,3},{2}}
   {{1},{2,3}}   {{1,3},{2}}
   {{1},{2,3}}   {{1,2},{3}}
  {{1},{2},{3}}   {{1,2,3}}
   {{1},{2,3}}   {{1,2},{3}}  {{1,3},{2}}

Crossrefs

Cf. A000110, A000258, A008277, A059849, A060639, A096827, A181939.

Cf. A318389, A318390, A318391, A318392, A318394, A318531.

Sequence in context: A117157 A267013 A376918 * A057857 A352969 A091233

Adjacent sequences: A318529 A318530 A318531 * A318533 A318534 A318535

Keyword

nonn,more

Author

Gus Wiseman, Aug 28 2018

Status

approved