(*  exp(x) function:  Total( Table( 2.^j/j!,{j,0,22} ) )  *)

x = 2.;
prod = x;  (*  x^1  *)
fact = 1.;  (*  1!  *)
acc = fact;  (*  x^0/0!, first result of sequence  *)
Do( AddTo(acc, prod / fact);
 TimesBy(prod, x);
 TimesBy(fact, j);
 , {j, 2, 23});

acc