The sum of the primes below 10 is
Find the sum of all the primes below two million.
Just two things I felt like mentioning:
Thing number one
I got tired of the page 2 stuff. So, I swapped all the <!–nextpage–> things with <!–more–> and a header. Which means that the solution will now be on the same page as the problem. (Although not on the index page).
Thing number two
My brother puts his whole solution on a public subversion repository, which is a very good idea. Following his good example,
I did a repository dump of my local VisualSVN Server and… undumped(??) it into one I set up here on my web host which I will be using from now on instead.
Update: SubVersion turned out to be a bit blah sometimes, so I am trying out Mercurial now instead. The repository has been converted and published on BitBucket. Mercurial seems a lot nicer than SubVersion so far. You can find a very good introduction at hginit.com.
Thing number three
Ok, ok, the topic says two, but I just figured I should maybe mention one more thing. You see, the code you will find in my aforementioned subversion repository cannot be run. Like, there is no main method or anything there. That is because I am trying to teach myself how to use test cases, etc. So, instead of creating an executable program for each problem or one program with fancy “Solve problem #n”-buttons, I decided to just do it all in test cases. So, my solutions are actually found as part of the test project (well, the running of them anyways). I am using TestDriven.net to run them, and it works great. This way I can also do a lot of changes, and then just run my tests and make sure that all my solutions still calculate correctly. Awesome stuff.
A Pythagorean triplet is a set of three natural numbers, for which,
There exists exactly one Pythagorean triplet for which,
Find the product abc.
Find the greatest product of five consecutive digits in the 1000-digit number.
By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13.
What is the 10001st prime number?
I am a total LaTeX newbie though, so I often struggle a bit with… getting it right. Trying it out by previewing WordPress posts is sloooow, so I decided to create myself a simple test-rig. A simple web page with a form and a button.
Let me know if you like it: tools.geekality.net/wp-latex
The sum of the squares of the first ten natural numbers is,
The square of the sum of the first ten natural numbers is,
Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 — 385 = 3640.
Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.