Talk:Table of prime factors
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[edit] Multiplication symbol, 1, sum function
Why the "1·"? That is not needed and a bit odd. - Patrick 11:49 May 6, 2003 (UTC)
- Jacquerie27, I've checked the table and it is correct. I agree with Patrick and I propose that we omit the 1s since we know that 1 is a divisor/factor of every integer. I would also change the function FacSum(n) to more 'common' additive function a0(n) (where a0(n) = FacSum(n)-1). Perhaps it is really odd, but in fact it does not really matter if we include 1s or not. I am also glad that you've used · notation for a multiplication instead of ×, although many here use the last one. I prefer the first one, but I do not own wikipedia :-) On the other side at the Table of divisors we should leave 1s as they are, since a 'common' multiplicative arithmetic function τ(n) == d(n) == NumDiv(n) returns them for all n. But nevertheless nice work. I also like colors very much. And I do not know if all browsers show them well. I know there were some problems with the tables for some well-known planets and stars. (See Earth|Sun|Betelgeuse for instance). Best regards. --XJamRastafire 00:46 May 7, 2003 (UTC)
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- Thanks a lot, and that sounds good. I've got a program to do the tables, so I can create and adapt them easily. Let me know if you'd like to see anything else like this. Your English is v. good, btw, but the approach to no mistakes outside your mother tongue is an asymptotic curve (if I've got that right). Jacquerie27 08:42 May 7, 2003 (UTC)
[edit] Prime factors of One
The prime factors presented in the Table of prime factors are (is) 1. However, I would prefer to see {} or 
as the set of prime factors and {1} as the set of divisors. So, I will include a note that 1 does not have any prime factors and empty the table cells. Gebruiker:Dedalus 08:12, 15 Feb 2005 (UTC)
[edit] WP:FLC
I was wondering if this should be a Wikipedia:Featured list, since it seems to meet most of the criteria: references would be needed, although this is just arithmetic so it is difficult to know what sort of references there would be, and an image would also be good, although, again, what images would be relevant?
One question: is there a reason for the table stopping at 1002, apart from it being the first convenient number greater than 1000 that is divisible by 3 (to fit into 3 columns)? Why not 1000 and 2 or 4 or 5 columns? -- ALoan (Talk) 13:39, 3 August 2005 (UTC)
[edit] too many redlinks
All the redlinks to numbers that fail to meet WP:NUM standards should be removed! Xtifr tälk 09:35, 23 October 2006 (UTC)
[edit] Why sum of prime factors?
Why list the sum of prime factors? It seems to be a rarely used function and I cannot think of practical uses for viewers of this table. Prime factors are meant to be multiplied, not added. Number of prime factors (Big Omega function), and number and sum of divisors (Divisor function) are more used functions. But I would probably prefer to only list the prime factors in the table. Then it really lives up to its name. If any reader is interested in the sum of prime factors then it's easily computed in the head, considering that the second-largest prime factor is at most 31. Another thing: I would prefer the number of rows being a multiple of 100, so there is a simple relation between numbers in the same row. Editing a large computer generated table is hard. Maybe somebody (e.g. me) could make an easily modified public domain program in a common language to generate the table. Or is Wikipedia a bad place for such things? PrimeHunter 15:45, 25 October 2006 (UTC)
[edit] New table format
I made major changes to the table today (November 21 2006). Here is the latest version before these changes.
- The sum of prime factors was removed because it seemed of no use.
- The formerly long table was broken into 10 sections, one for each 100 numbers.
- Multiple factorizations on the same line are now part of separate subtables with interval headings, and spaces between. I think this makes it easier to locate numbers and read the tables. It also means the source becomes in numerical order. I chose 20 lines with 5 factorizations per line.
- The color in the columns was removed, reducing article size by around 60%. Colors were unnecessary after the subtables were separated by spaces.
- All exponents now use superscripts and look similar, i.e. special characters for exponents 2 and 3 are not used.
- Only those number articles which exist or redirect November 19 2006 are linked.
The new tables were generated by a simple PARI/GP program. The tables in this article version were generated by this program version. It's easy to modify the program. I don't recommend manual editing of the tables, but I or my program have no special rights to the article. I watch this talk page and my own pages for suggestions. If you modify the program on your own and insert the output in the article, then I recommend making the modified program available with a link on this page.
If there should later be support for reformatting to one number per line with more details about that number, similar to table of divisors, then I could probably adapt the program. PrimeHunter 02:46, 21 November 2006 (UTC)
