# Talk:2046: Trum-

This is not that weird. If names were random then it would be a 1 in 26^4 = 456976 chance of a particular president matching another for the first 4, but this is a "Birthday Problem" with 44 presidents, so the probability of any two presidents sharing the first 4 characters is 1-(456976!/(456976^44 (456976 - 44)!)), which wolfram alpha is giving as 0.206%

- Yes, but we already "fulfilled our obligation" after the sixth president :) Zachweix (talk) 15:59, 14 September 2018 (UTC)

An approximation to the correct probability would be to do 44^2/(2 x 26^4) which would give about 0.2% chance of this happening. So fairly weird, but as the comic suggests, many things about this presidency are weirder than 0.2%.

- I love that we are now having a mathematical discussion about how weird things are in the presidency. Zachweix (talk) 15:58, 14 September 2018 (UTC)

Should we mention Andrew Johnson and LBJ, perhaps in a "Trivia" section? Obviously Johnson is a very common surname, but they're still unrelated presidents that share the first (and only) 7 characters of their last name. (Are there other pairs of presidents that share at least the 3 first letters of their surnames besides AJ/LBJ and HST/DJT?) 172.69.62.160 16:25, 14 September 2018 (UTC) ...And, upon reflection, I just realized Harding shares the first 3 letters with the Presidents Harrison, so that's one(?) more example.