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: 4, 20, ['O', '1087', 'r', '7529', 'K', 'f', 'B', 'k', 'b', 'O', '2343', 'n', '8565', '7791', 'C', 'N', '5369', '1913', '5137', 'D']

D513719135369NC77918565n2343ObkBfK7529