What do the following U.S. presidents (and no others) have in common? George Washington John Adams Ulysses S. Grant Theodore Roosevelt Herbert Hoover Richard Nixon
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Hoover and Nixon were Quakers, so that's something. Not the answer though.
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I broke down and Googled. They all served as President at least partly when there were no living ex-presidents.
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It's interesting that the last two presidents who share this property were both Quakers...
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Indeed. This was inspired by seeing something on Twitter this morning about how the set of living ex-presidents ought to do something related to COVID-19.
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Replying to @davidbaron @wycats
I'm also a little impressed that you and @xgolferx figured it out. Thought maybe too hard. I'd planned a hint about how building the same list based on the list of British Monarchs since the Acts of Union 1707 en.wikipedia.org/wiki/List_o… would include all except for George VI.

Mar 28, 2020 · 8:54 PM UTC

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It wasn't a trivial googling but some investigative journalism training back in college provided some good skills. The main approach I used was googling various collections of 4/6 of them until I hit on the answer. It's too obscure of a question for the obvious search to work.
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for me the third hit for "Washington Adams Grant Roosevelt Hoover Nixon" is washingtonexaminer.com/six-p… which pretty much has the answer right there
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