The total number of elements(ordered pairs) in all equivalence relations on {1,2,...,n}.
A175716
The total number of elements(ordered pairs) in all equivalence relations on {1,2,...,n}.
Terms
- a(0) =0a(1) =1a(2) =6a(3) =27a(4) =120a(5) =560a(6) =2778a(7) =14665a(8) =82232a(9) =488403a(10) =3062980a(11) =20221520a(12) =140134404a(13) =1016698813a(14) =7703878042a(15) =60833235795a(16) =499592325152
External references
- oeis: A175716