About the Euler Project
Mathematics consists of proving the most obvious thing in the least obvious way. (George Pólya, Hungarian mathematician)

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Mathematics consists of proving the most obvious thing in the least obvious way. (George Pólya, Hungarian mathematician)

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In this loose series I plan to solve the math riddles from the Euler project one by one.
The Task The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. This task is so easy that it is almost not worth its own post. The reason is because it is identical to Task 7, "10001st prime" except...
In our previous post, we introduced how to utilize Discrete Event Simulation (DES) in PicoLisp. Now, let's explore another application: a railroad model simulation that includes tracks and trains. The visualization is ASCII-based, so feel free to unl...

The Dining Philosophers

In this post, we will introduce the concept of co-routines and how they are handled in PicoLisp. This will be the foundation for the subsequent posts on Discrete Event Simulation and finally a couple of examples, including an ASCII model railway simu...

One of the many nice things of PicoLisp is that it comes with a built-in database. This makes it easy to collect and store our own data, for example via a mobile app. But not all data is best represented in tables and lists: sometimes a colorful litt...

In the last two posts, we have built a little app that shows the current location and displays the nearest ice cream shops: https://picolisp-explored.com/an-openstreetmap-app-written-in-picolisp-pt-1 https://picolisp-explored.com/an-openstreetmap-ap...

This series will be about the tasks from the Euler Project, which is a a project page for mathematical riddles with increasing difficulty.
After signing up, you can upload your solutions in order to get credits. At the moment there are 725 riddles at 29 levels (25 riddles per level). As you can see, the first task has been solved by almost a Million people (the last one not even by 500...).

The Euler Community permits sharing the results for task 1-100.
All of the tasks can be solved on a normal PC within a few minutes if the algorithm is implemented correctly. Many of the tasks have a little twist, meaning that they could be implemented in a straightforward way, but also in a more interesting, "smart" way.
The roots of functional programming lie in the algorithmic computation of mathematical problems, so it's not surprising that PicoLisp often enables us to write extremely concise and short code in order to solve these tasks. Similarly to the Rosetta code series, the main purpose of this series is to get more familiar with PicoLisp and its syntax and concepts.
When we find some interesting functions, we will pick them up for deeper discussion in the "PicoLisp Explored" Series.

Well, that's the plan!
If you want to prepare, here is the task for tomorrow:
If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.
Find the sum of all the multiples of 3 or 5 below 1000.
https://projecteuler.net
https://imgs.xkcd.com/comics/mathematical_symbol_fight.png