# 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% 141.101.99.185 (talk) *(please sign your comments with ~~~~)*

- Yes, but we already "fulfilled our obligation" after the sixth president :) Zachweix (talk) 15:59, 14 September 2018 (UTC)
- That would be the lower boundary, because you assume all letters are equally likely to occur. Some n-grams will have a higher probability than others. E.g. it is far less likely for the second letter to be a Q than to be a U,so a better estimate would involve Markov chains including the probability of all letters on a certain position, given the previous letters etc.141.101.76.58 05:46, 15 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%. 162.158.155.194 (talk) *(please sign your comments with ~~~~)*

- 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)

- They ARE related, distantly. https://www.geni.com/path/Lyndon-B-Johnson-36th-President-of-the-United-States+is+related+to+Andrew-Johnson-17th-President-of-the-USA?from=6000000002045454764&to=361204095530004567 SDSpivey (talk) 19:18, 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. 162.158.186.246 (talk) *(please sign your comments with ~~~~)*

So we discount Presidents Adams, Bush, Cleveland, Harrison and Rosevelt as being related, or being the same person. We have the following common starts: Bu (3 names), Cl, Ha (3 names), Ta, Har, Trum and Johnson. Also A, B, C, F, G, H, J, M, P, R, T and W. 162.158.154.241 16:49, 14 September 2018 (UTC)

If you count Buren as opposed to Van Buren then you have 4 starting Bu and 2 starting Bur 162.158.155.146 16:52, 14 September 2018 (UTC)

Tyler and Taylor is weirdly close, in a "look elsewhere effect" kind of way. Although the fact that you elected a president whose name means "fart" in British English has got to be weirder. 162.158.155.158 (talk) *(please sign your comments with ~~~~)*

**Shouting about Trump**

I'm really with you... But an explanation has to be done politely. This Wiki focuses on explaining the comic, any personal opinions should be considered carefully. And I admit that I also cannot easily withstand. --Dgbrt (talk) 20:25, 14 September 2018 (UTC)

Only 39 unique names for 45 presidencies (44 presidents). Over a third (14/39) of the names end with the letter N. Patmiller (talk) 20:36, 14 September 2018 (UTC)

Is this factoid worth adding to the trivia section? Trump is the only president whose entire last name is needed for disambiguation. In other words, except for identical last names, every other president can be identified with just some of the first letters of the last name (some needing only the single first letter, and even Truman, the next “worst” case, needing only Truma to disambiguate from Trump.108.162.219.214 03:49, 16 September 2018 (UTC)