Timeline for How many combinations does Android pattern have? [closed]
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
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| Jan 10, 2014 at 20:54 | history | closed |
Ryan Budney Stefan Kohl♦ Boris Bukh Anton Petrunin Igor Rivin |
Not suitable for this site | |
| Jan 10, 2014 at 18:07 | comment | added | Ryan Budney | Regardless of the number of combinations, this isn't a very secure way to lock a phone unless you thoroughly clean the screen after touching it. | |
| Jan 10, 2014 at 17:52 | comment | added | Nathaniel Johnston | As a follow-up to my previous comment (which I can't edit anymore) -- the 4th term of the OEIS entry was indeed incorrect (it was 1642 rather than the correct 1624). I have since corrected it. The final answer to this problem is 389112 (not 389130). | |
| Jan 10, 2014 at 17:44 | review | Close votes | |||
| Jan 10, 2014 at 20:56 | |||||
| Jan 10, 2014 at 17:43 | comment | added | The Masked Avenger | Start by enumerating legal first arrows. If I understand the rules, there are at most 40 such. Then do legal second arrows (If you use symmetry, there are 7 branches to explore). You now have a handle on a good upper bound, as there will be a little more than 6! ways to finish each branch. This question is better asked at a different forum. | |
| Jan 10, 2014 at 17:39 | review | First posts | |||
| Jan 10, 2014 at 17:52 | |||||
| Jan 10, 2014 at 17:36 | comment | added | Nathaniel Johnston | See OEIS: A163889. The total number of unlock patterns is A163889(4) + ... + A163889(9) = 389130. [Edit: the OEIS might have A163889(4) wrong -- can anyone verify if that term is 1624 or 1642?] | |
| Jan 10, 2014 at 17:21 | history | asked | travis bickle | CC BY-SA 3.0 |