Dividing $61!$ by $3$ as we can.
Highest power of a prime $p$ dividing $N!$
What is the difference between AOSP and AOKP? I have a Java process that opens a file using a FileReader. How can I prevent another (Java) process from opening this file, or at least notify that second process that the file is already opened? Does this automatically make the second process get an exception if the file is open (which solves my problem) or do I have to explicitly open it in the first process with some sort of flag or argument? To clarify: I have a Java app that lists a folder and opens each file in the listing for processing it. It processes each file after the other. The processing of each file consists of reading it and doing some calculations based on the contents and it takes about 2 minutes. I also have another Java app that does the same thing but instead writes on the file. What I want is to be able to run these apps at the same time so the scenario goes like this. ReadApp lists the folder and finds files A, B, C. It opens file A and starts the reading. WriteApp lists the folder and finds files A, B, C. It opens file A, sees that is is open (by an exception or whatever way) and goes to file B. ReadApp finishes file A and continues to B. It sees that it is open and continues to C. It is crucial that WriteApp doesn't write while ReadApp is reading the same file or vice versa. They are different processes. Is there a standard function in C that would return the length of an array? I'm running Drush on a host that has multiple versions of PHP installed. By default, php --version would give you 5.2.x, but php53 and php54 are also available. So in my .bash_profile I have alias php='php53' (php --version = 5.3.13), which makes Drush work for some commands.  However, I still get "Your command line PHP installation is too old. Drush requires at least PHP 5.3.2" messages for some very useful commands.  A couple of really annoying instances:   drush pm-update will report that it has backed up and then updated all modules and core successfully, then return the PHP version error and restore all backups. In verbose mode, the command that comes before the error is: php /home/[username]/drush/drush.php  --backend=2 --verbose --root=/home/[username]/webapps/drup --uri=http://[domain name]  pm-updatecode-postupdate 2&gt;&amp;1 drush archive-dump will immediately return the PHP version error   The other commands I have tried so far work fine. I'm not sure why this would be, if Drush is sometimes using the php53 binary, and other times not, or if it just has trouble detecting the version correctly, but some very important features are broken for me. Probability of a 2 pair in poker What is wrong with my method of find the probability of a 2 pair?  For the first card we have 52 choices, one this is picked( call it A) we have 3 choices(different suite than A but this same value) for the second card, ( lets call this card B). Now we have AB, to we have to throw away 2 more cards so we don't have 3 of a kind or a four of a kind. Therefore one our third card we have 48 choices and on our fourth card we have 3 choices again similar to above.  On our last card we only have 44 choices left. So the probablity of getting a 2 pair should be (52*3*48*3*44)/(52 choose 5).  But this isn't correct.     Note: I edited this to "2 pair"; the original version was wrong. How do I parse command line arguments in Bash? How can I produce the text Word_one_two in LaTeX?  I tried:  Samp\_Dist\_Corr   But, it doesn't quite look right. Also, I want it in the typewriter font, so actually, I'm doing:  \texttt{Samp\_Dist\_Corr}   I find it looks a bit like the underscore is merging in to the bottom of the "D", but maybe it's just because of the typewriter D? Is the below a valid circuit implementation and are there any things to watch out for? It's a simplification of the larger circuit but the crux of it is that I need to sink current into two GPIO input pins. The pins are signified by the 1 and 0.  Also, would a diode on the pins be advisable?    Edit: Here's the non-simplified circuit. The question relates to the 3.3v part of it. In essence, the timer and decade counter sequentially pulse current, 'activating' the transistors one at a time. The keypad is a simple matrix keypad. What I'm wondering if I can do is to put a GPIO pin on the line between the keypad and ground. The intended effect is that, when a button on the keypad is pressed, 2 pins will change state - this signifies the row and column.  Note that some of the resistance and capacitance values are notional at the moment. Can't access select https sites on Linux over PPPoE My internet connection used to be a direct LAN connection to my provider. Back then, everything would load fine on both Windows and Ubuntu (dual boot). However, a while ago they started needing me to dial (PPPoE) using a username and password. Gateway, subnet mask, IP, DNS servers all stayed the same. But since then, I haven't been able to browse certain websites on Ubuntu, even though there have been no such issues on Windows. Some example websites are -  (although share.ovi.com loads fine, and nokia.com loads fine),  (works on Chrome(ium) and Opera but not on Firefox (both 3.6 and 4)) Mozilla  and other random websites.  Some of the websites that don't load show timeout messages and for some websites (like the moz addons one), the browser will keep trying to load without an end (I've left it like that even for hours but not noticed anything different happen).  I have tried changing the DNS servers to public ones. I have even tried booting from a Fedora LiveCD and then changing the DNS to those (and even to the ones of OpenDNS), but the exact same thing happens. What could be inherently wrong with some config within Linux itself that is causing this problem?  Does anyone know why this is happening and how it can be fixed?  Note: This question has been  on SU, but not gotten any responses.  Update: Just saw  that someone else was having similar problem and solved it by putting a NetworkManager.conf file in /etc/NetworkManager. What needs to be in that file? If I have example.com, and blog.example.com, do search engines see those as one site or two? Will using subdomains hurt SEO? I have some technical reasons why I can't use example.com/blog. `time echo` got no output Do I need to re-check my bags when flying into the US on a transit through Newark Airport? Travveling with SAS 907 from Oslo, Norway to Newark Terminal B. Transfer to Terminal C and further with United 239 to Nashville. Do I have to pick up the luggage at terminal B and bring it to terminal C? Are moving objects producing stronger gravity fields? If the strength of gravitational influence exerted by a body is derived from its mass and energy then is it true that a moving object which has some kinetic energy should also produce stronger gravitational pull than a static/slower one?  If that's correct then would it be also possible for an object moving fast enough to produce gravity so strong that it would collapse into a (fast moving) black hole? When does a locational distinction change its suffix and capitialization in a proper name? No internet after upgrade to 17.10 Can I use Divine Intervention or Wish to regain Wish? After reading this question on , I started wondering if there are ways for them to regain that ability.  I figured a Divine Intervention is probably strong enough as that is a god's power, as well as a second caster casting wish to undo the first wish (and thereby undoing its effects).  Are these valid ways of regaining the ability to cast wish? I'm working with a date in this format: yyyy-mm-dd.  How can I increment this date by one day? Is there a way to turn option strict off for just a single line of code?    I'm doing some maintenance work and I need to "cheat" in just one place and I don't want to lower the standard for the entire file. Do eyeballs exhibit chromatic aberration? Fairly straightforward question. If not, why not?  I suspect that if they do, it is not perceived due to the regions of highest dispersion being in one's region of lowest visual acuity. Durrett Example 1.9 - Pairwise independence does not imply mutual independence?