Collatz function data for 2^57885161 – 1 (#4 known megaprime) Posted on 10.12.2019 by Andrey S. Shchebetov / Андрей Щебетов We publish our first data on the Collatz function for 257885161 – 1 (#4 known megaprime) and two of its odd neighbors located at ±8. All tested numbers supported the Collatz conjecture.