Dictionaries: General Computing Medical Legal Encyclopedia Collatz conjecture Word: Word Starts with Ends with Definition The Collatz conjecture , also known as the n +1 conjecture , the Ulam conjecture or the Hailstone sequence , was first stated around 1950 and concerns the following process: # Pick any positive integer The integers consist of the natural numbers (0, 1, 2, ...) and their negatives (1, 2, 3, ...; 0 is equal to and therefore not included as a separate integer). The set of all integers is usually denoted in mathematics by Z (or Z in blackboard bold, ), which stands for Zahlen (German for "numbers"). They are also known as the whole numbers , although that term is also used to refer only to the positive integers (with or without zero). Click the link for more information. n # If n is even, divide it by two; if it is odd, multiply it by three and add one. If n = 1, stop; else go back to step 2. For instance, starting with n = 6, we get the sequence 6, 3, 10, 5, 16, 8, 4, 2, 1. The Collatz conjecture says that this process always stops, no matter what the start value.  
