Let P(A) be the power set of an n-element set A. Then a(n) = the number of pairs of elements {x,y} of P(A) for which either 0) x and y are intersecting but for which x is not a subset of y and y is not a subset of x, or 1) x and y are intersecting and for which either x is a proper subset of y or y is a proper subset of x, or 2) x = y.
A134064
Let P(A) be the power set of an n-element set A. Then a(n) = the number of pairs of elements {x,y} of P(A) for which either 0) x and y are intersecting but for which x is not a subset of y and y is not a subset of x, or 1) x and y are intersecting and for which either x is a proper subset of y or y is a proper subset of x, or 2) x = y.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =23a(4) =96a(5) =407a(6) =1716a(7) =7163a(8) =29616a(9) =121487a(10) =495276a(11) =2009603a(12) =8124936a(13) =32761367a(14) =131834436a(15) =529712843a(16) =2125993056a(17) =8525430047a(18) =34166159196a(19) =136858084883a(20) =548012945976
External references
- oeis: A134064