Input (grade 13): Generalization The binary representation of 2n & minus; 1 is the digit 1 repeated n times, for example, 25 & minus; 1 = 111112 in the binary notation.
Output (grade 9): The binary representation of 2n & minus; 1 is n repetitions of the digit 1. For example, 25 & minus; 1 = 11111 in binary.