Number of 4-element families of an n-element set such that every 3 members of the family have a nonempty intersection.
A051365
Number of 4-element families of an n-element set such that every 3 members of the family have a nonempty intersection.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =3a(4) =275a(5) =8475a(6) =192385a(7) =3831093a(8) =71466675a(9) =1285857975a(10) =22632300245a(11) =392522268633
External references
- oeis: A051365