Definition: In this task, you are given inputs i, j, and A, where i and j are integers and A is a list. You need to find all elements of A from the ith element to the jth element, reverse the order in which they occur, and then concatenate them to output the resultant string. i and j will be non-negative, and will always have a value less than the length of A. i will always be less than j. Perform the operations in order, i.e., do not concatenate the elements and then reverse the string.
Input: 7, 21, ['Q', 'O', 't', 'U', 'j', 'h', 'X', 'm', '3805', '2443', '8247', '8541', 'J', 'K', 'o', '5287', '2291', '2435', 'U', '4289', 'n', 'A', '9327', 'H', 'x', 'W', 'E', '2659', '7503']

n4289U243522915287oKJ8541824724433805mX