Timeline for Integers in a triangle, and differences
Current License: CC BY-SA 2.5
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 7, 2010 at 19:16 | comment | added | ndkrempel | Unsurprisingly, none for n=10 - that took 30 minutes. It's interesting to allow a larger N in the original question (so you just use some of the numbers 1...N, but still no repetitions). Then it would be nice to know the asymptotics of the smallest N such that a triangle exists, as a function of n. For n=6, N=22, exactly two exist (missing the number 15). For n=7, N=29, there aren't any. | |
| Dec 7, 2010 at 18:35 | comment | added | ndkrempel | @HenrikRüping: Thanks for that suggestion, the n=9 computation takes less than 4 minutes now. | |
| Dec 2, 2010 at 10:14 | comment | added | HenrikRüping | Noting, that the biggest number must always be placed in the first row, the second biggest number in the first row or below a bigger number etc. should speed up the program a lot (if u didn't use that already). | |
| Dec 2, 2010 at 5:56 | comment | added | ndkrempel | Since I set it running before more definitive answers came in, I may as well report there are none for n = 9 either, although that took about 6 hours (without improving the method). | |
| Dec 1, 2010 at 22:48 | comment | added | ndkrempel | Update: none for n = 8. That took about half an hour (using Ruby 1.9), so a more clever approach or faster language/computer may be required soon. | |
| Dec 1, 2010 at 22:08 | comment | added | ndkrempel | Ok, using a slightly less naive search, I've shown there are none for n = 7 either. | |
| Dec 1, 2010 at 21:10 | history | answered | ndkrempel | CC BY-SA 2.5 |