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, 20, ['F', '6615', 'X', '7555', '859', '8491', 'y', 'H', '6749', 'r', '8041', 'j', 'w', 'b', '409', '1113', 'A', '3759', 'f', '3739']

3739f3759A1113409bwj8041r6749Hy