Consider the following operation on an arbitrary positive integer:
-
If the number is even, divide it by two.
-
If the number is odd, triple it and add one.
Conjecture is that, starting from any positive integer, the serie will end by the integer 1.
Still unproven.
"On the 3x + 1 problem" - www.ericr.nl/wondrous/index.html
"La conjecture de Syracuse" - https://www.cristal.univ-lille.fr/~jdelahay/pls/053.pdf
"Path records" - https://pcbarina.fit.vutbr.cz/path-records.htm