Number of doubly-surjective functions f:[n]->[4].
A224542
Number of doubly-surjective functions f:[n]->[4].
Terms
- a(0) =2520a(1) =30240a(2) =226800a(3) =1367520a(4) =7271880a(5) =35692800a(6) =165957792a(7) =742822080a(8) =3234711480a(9) =13803744864a(10) =58021888080a(11) =241116750624a(12) =993313349544
External references
- oeis: A224542