Number of 3-element proper antichains of an n-element set.

A051303

Number of 3-element proper antichains of an n-element set.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =1a(4) =30a(5) =605a(6) =9030a(7) =110901a(8) =1200150a(9) =11932285a(10) =111885510a(11) =1006471301a(12) =8786447670a(13) =75039565965a(14) =630534185190

External references