Timeline for Positive integers $n$ that divide $\sigma_2(n)$
Current License: CC BY-SA 2.5
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 19, 2011 at 7:50 | vote | accept | Luis H Gallardo | ||
| Jan 12, 2011 at 7:21 | answer | added | Wadim Zudilin | timeline score: 4 | |
| Jan 12, 2011 at 3:09 | comment | added | Gerhard Paseman | sorry, k < (p^3)/4. Makes it more of a challenge, but still is limiting. Gerhard "Ask Me About System Design" Paseman, 2011.01.11 | |
| Jan 12, 2011 at 3:09 | answer | added | Alex B. | timeline score: 1 | |
| Jan 12, 2011 at 2:04 | answer | added | alpoge | timeline score: 2 | |
| Jan 12, 2011 at 0:09 | comment | added | Matthew Conroy | Just a note that even without the mod 4 condition on p, there is only one example of such an n with p and q both < 7919, which suggests to me that the condition may not be needed to prove impossibility (for sufficiently large n). | |
| Jan 11, 2011 at 23:13 | comment | added | Gerhard Paseman | If you look more closely, you need q^2 divides 1 + p^2 and p divides (1 + q^2 + q^4). This means there is k < p, k=3 mod 4, with kp = (1 + q^2 + q^4). I bet it is not far from this to a proof of impossibility, or a small counterexample. What have you tried? Gerhard "Ask Me About System Design" Paseman, 2011.01.11 | |
| Jan 11, 2011 at 22:46 | history | asked | Luis H Gallardo | CC BY-SA 2.5 |