Timeline for Natural numbers that cannot be expressed as a difference between a square and a prime?
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 24, 2014 at 10:44 | comment | added | Emil Jeřábek | @Mike: How do you show that a number that cannot be expressed like this must be a square in the first place? | |
| May 24, 2014 at 6:01 | comment | added | Mike | I dont konw what's the question,if is this: "The question is whether all the numbers which cannot be expressed like this are of this form i.e. n2 where 2n+1 is composite.", my answer is : yes,it is. If $2n+1$ is composite,$\ n$ must of the form $2ij + i + j,\ i, j \in\mathbb{Z},\ 1 \le i \le j\ $, see [Sieve of Sundaram](en.wikipedia.org/wiki/Sieve_of_Sundaram). Let $n = 2ij + i + j,\ $this question is equivalent to prove :$(n+x)^2 - n^2 $ is composite,where $x \in\mathbb{Z^+}$, this is a elementary question, I dont understand this is related to some conjecture. | |
| May 23, 2014 at 15:07 | answer | added | Robert Israel | timeline score: 3 | |
| May 23, 2014 at 14:50 | vote | accept | A.K. | ||
| May 23, 2014 at 13:50 | answer | added | Joni Teräväinen | timeline score: 21 | |
| May 23, 2014 at 13:10 | comment | added | A.K. | A similar question is asked at math.stackexchange.com/questions/613256/… | |
| May 23, 2014 at 13:08 | history | undeleted | A.K. | ||
| May 23, 2014 at 13:07 | history | deleted | A.K. | via Vote | |
| May 23, 2014 at 13:03 | review | First posts | |||
| May 23, 2014 at 13:07 | |||||
| May 23, 2014 at 12:44 | history | asked | A.K. | CC BY-SA 3.0 |