January 2012
3 posts
December 2011
4 posts
“My years spent as an engineering student taught to be logical and linear, but...”
– The Online Photographer: Kirk’s Take (Kirk Tuck #2)
November 2011
8 posts
2 tags
Problem 193
Squarefree numbers.
Found searching for “project euler” in OEIS.
October 2011
18 posts
2 tags
Problems 114 to 117
114 - Investigating the number of ways to fill a row with separated blocks that are at least three units long
115 - Finding a generalisation for the number of ways to fill a row with separated blocks
116 - Investigating the number of ways of replacing square tiles with one of three coloured tiles
117 - Investigating the number of ways of tiling a row using different-sized tiles
These all flow...
2 tags
Problem 187
Semiprimes.
Easily done if you have a few million primes on hand.
There’s a sequence in Sloane that gives the answer directly, too!
2 tags
Problem 100
Finding the number of blue discs for which there is 50% chance of taking two blue.
I started researching the hypergeometric distribution and thought about comparing it to a binomial distribution at large numbers before twigging that if you expand the problem it’s a quadratic Diophantine equation. There’s an online solver that provides factors for these equations and after that it was...
2 tags
Problem 203
Squarefree binomial coefficients.
I had in mind optimisations in only calculating half the triangle, but in the end it didn’t signify. I used the Pari issquarefree() function. Biggest issue was forgetting telling Perl to use arbitrary precision integers.
2 tags
Problem 119
Investigating the numbers which are equal to sum of their digits raised to some power.
I turned this over in my mind trying to find some limit so I didn’t have such an enormous search space. Then I found A023106 in Sloane which gives all but the last few terms, and then it was really fast to brute force.
To be quite honest this was a bit easy for this level.
“If Jobs managed to get consumers to buy into the “cool cult,” what...”
– (Notes on) Politics, Theory & Photography: Can We Get a Grip, Please?
The backlash has begun! But to be honest, this is what I thought from the beginning. Those mourning Jobs are afraid that they won’t be getting as many cool gadgets in the future. And that’s a sad indictment of...
1 tag
September 2011
8 posts
“I don’t fully understand it. But a large part of it, it seems obvious, is the...”
– Defeatism
“The website is not clean and simple enough! We need to add more stuff until it...”
– (via clientsfromhell)
August 2011
7 posts
9 tags
“Former white-collar workers are also surprised by the demands of manual labor.”
– (from www.nytimes.com)
July 2011
1 post
June 2011
5 posts
