Find the number of onto function between two sets `A = (1, 2, 3, 4) and B = (4,5)`

Find the number of onto functions from a set containing A = {1, 2, 3, 4, 5) to another set B = {a, b, c, d) such that f(1) = a.

Find the number of all onto functions from the set A={1,2,3, ,n} to itself.

Find the number of all onto functions from the set A={1,\ 2,\ 3,\ ,\ n} to itself.

Find the number of all onto functions from the set A={1,\ 2,\ 3,\ ,\ n} to itself.

Find the number of all onto functions from the set {1,2,3..,n} to itself.

Find the number of all onto functions formthe set {1,2,3,….,n} to itself.

Find the number of all onto functions from the set {1,2,3 …... n} to itself.