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: 11, 21, ['J', 'l', 'G', '5399', '4799', 'B', '5037', '4005', '9291', '743', '8285', '7697', '121', 'W', 'n', 'r', 'T', '4209', 'H', 'o', 'u', 't', 'n', 'R']

uoH4209TrnW12176978285