Hypothetical manipulative theory, sheldon 73 theory. 73 - Sheldon number. Swapping numbers 73 we get number 37 73 is the 21 prime number in the sequence. Swapping the numbers in number 21 we get the number12 4 level number 4 + 4 level number 8 4+4+4 level number 12 I'm not a professional trader. I'm just looking for answers.