Timeline for Can exist a positive integer number $x$ such that $a_1=x$ and $a_n=2a_{n-1}+1$ are not prime for all $n \ge 1$?
Current License: CC BY-SA 4.0
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| when toggle format | what | by | license | comment | |
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| Jul 4 at 16:02 | comment | added | GH from MO | I can repeat my comment below David E Speyer's post. All this is essentially due to Erdős. | |
| Jul 4 at 10:57 | history | answered | Gerry Myerson | CC BY-SA 4.0 |