A318130 Number of sets of subsets of {1,...,n} with intersection {}.

2, 3, 11, 219, 64595, 4294642035, 18446744047940725979, 340282366920938463334247399005993378251, 115792089237316195423570985008687907850547725730273056332267095982282337798563

Offset

0,1

Links

Table of n, a(n) for n=0..8.

Formula

Binomial transform of A131288.

Inverse binomial transform of A119563(n) = 2^(2^n) + 2^n - 1.

Example

The a(2) = 11 sets of sets:
  {}
  {{}}
  {{},{1}}
  {{},{2}}
  {{1},{2}}
  {{},{1,2}}
  {{},{1},{2}}
  {{},{1},{1,2}}
  {{},{2},{1,2}}
  {{1},{2},{1,2}}
  {{},{1},{2},{1,2}}

Mathematica

Table[Length[Select[Subsets[Subsets[Range[n]]], Or[#=={}, Intersection@@#=={}]&]], {n, 0, 4}]

Crossrefs

Cf. A000371, A001146, A003465, A119563, A131288, A318128, A318129.

Cf. A318128, A318129, A318131, A318132.

Sequence in context: A135161 A066100 A029497 * A109809 A211349 A096456

Adjacent sequences: A318127 A318128 A318129 * A318131 A318132 A318133

Keyword

nonn

Author

Gus Wiseman, Aug 18 2018

Status

approved