{1,2,3,4,5}rarr{1,2,3,4,5}" .Find the total number of function such that "f(f(x))=f(x)

If A={1,2,3,4} and f : A->A, then total number of invertible functions,'f',such that f(2)!=2 , f(4)!=4 , f(1)=1 is equal to:

If A={1,2,3,4} and f : A->A, then total number of invertible functions,'f',such that f(2)!=2,f(4)!=4,f(1)=1 is equal to:

If X={1,2,3,4,5} and Y={a,b,c,d,e,f} and f:X rarr Y , find the total number of functions .

If f:{1,2,3,4}rarr{1,2,3,4},y=f(x) be a function such that |f(alpha)-alpha|<1 for alpha in{1,2,3,4} then total number of functions are

Let A={1,2,3,4,5}, B={1,2,3,4) and f:A rarr B is a function, the

Let A={1,2,3,4,5}, B={1,2,3,4} and f:A rarr B is a function, then

Let A={1,2,3,4,5}, B={1,2,3,4} and f:A rarr B is a function, then

Let A={1,2,3,4,5} and f:A rarr A be an into function such that f(x) nex forall x in A . Then number of such functions f is: