Timeline for How Composite can $2^n-1$ be, infinitely often?
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Oct 16, 2017 at 16:29 | comment | added | Gerhard Paseman | Note that $2^{12} -1$ is a multiple of 105, giving that the ratio above is at most $16/35$ or about $0.457$. I would expect many small $n$ producing ratios in $(0.3,0.4)$ to be multiples of 12. I imagine the first $n$ to do so that isn't a multiple of 12 would have three or more decimal digits. Gerhard "Primitive Factors Grow Pretty Fast" Paseman, 2017.10.16. | |
| Oct 16, 2017 at 7:55 | comment | added | Vincent | @Dirk The Euler Totient function. $\varphi(n)$ is the number of numbers smaller than $n$ that are coprime to $n$. So $\varphi(n)/n$ is close to 1 for $n$ prime and and smaller if $n$ has more divisors. | |
| Oct 16, 2017 at 7:52 | vote | accept | kodlu | ||
| Oct 16, 2017 at 7:51 | vote | accept | kodlu | ||
| Oct 16, 2017 at 7:51 | |||||
| Oct 16, 2017 at 7:22 | history | edited | kodlu | CC BY-SA 3.0 |
added 53 characters in body
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| Oct 16, 2017 at 7:15 | comment | added | Dirk | Pardon my ignorance, but what is $\varphi$? | |
| Oct 16, 2017 at 7:12 | answer | added | Salvo Tringali | timeline score: 33 | |
| Oct 16, 2017 at 6:47 | history | edited | kodlu | CC BY-SA 3.0 |
fixed typo
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| Oct 16, 2017 at 6:25 | history | asked | kodlu | CC BY-SA 3.0 |