The number of unordered pairs (f,g) of functions from {1..n} to itself such that fg=gf (i.e., f(g(i))=g(f(i)) for all i).
A254569
The number of unordered pairs (f,g) of functions from {1..n} to itself such that fg=gf (i.e., f(g(i))=g(f(i)) for all i).
Terms
- a(0) =1a(1) =7a(2) =84a(3) =1540a(4) =37345a(5) =1145376a(6) =42402871a(7) =1849021504a(8) =93217426857
External references
- oeis: A254569