{"slug": "my-mathematical-regression", "title": "My Mathematical Regression", "summary": "A developer discovered their 10-year-old solution to Project Euler problem 15, which used a mathematical formula instead of brute force, highlighting a decline in their problem-solving skills since leaving academia.", "body_md": "#\n[My Mathematical Regression](/posts/my-mathematical-regression/)\n\nI came across my 10 year old repo for [project Euler](https://projecteuler.net/) solutions. (N.B! Euler spoilers onwards).\n\nNaturally it’s full of python files. One file stood out. It was just called `problem15.txt`\n\n.\n\nI pulled up the problem.\n\nI imagined getting this at work. I think I would reach for python. Maybe start with a naive brute force. Throw a bunch of loops together. If that didn’t solve it, reach for memoization. Dynamic programming, let’s go! (this is just me fantasizing. At work I would just give it to an AI and continue with my day)\n\nAnd let’s see how [I solved it when I was still an engineering student](https://github.com/aleda145/projecteuler/blob/master/problem15.txt)\n\n`problem15.txt`\n\n[⌗](#problem15txt)\n\n```\ndoesnt even need to program anything for this problem\nthere are 6 solutions to the 2x2 grid\nthere are 2 solutions to 1x1 grid\nthere are 20 solutions to a 3x3 grid\nthis follows the pattern of (2n) choose n\nso (2*20) choose 20 = 137846528820\n```\n\n*(If you aren’t familiar with discrete math, see the binomial coefficient for syntax)*\n\nI’m impressed by past self! And present me became sad. It feels like an Asimov book where the main character finds past knowledge, codified by the ancients. But it’s just me when I was in school.\n\nI remixed [this picture](https://pearlsofrawnerdism.com/?p=1252) to cope.", "url": "https://wpnews.pro/news/my-mathematical-regression", "canonical_source": "https://blog.dahl.dev/posts/my-mathematical-regression/", "published_at": "2026-06-19 11:06:04+00:00", "updated_at": "2026-06-19 11:37:31.663983+00:00", "lang": "en", "topics": ["artificial-intelligence"], "entities": ["Project Euler"], "alternates": {"html": "https://wpnews.pro/news/my-mathematical-regression", "markdown": "https://wpnews.pro/news/my-mathematical-regression.md", "text": "https://wpnews.pro/news/my-mathematical-regression.txt", "jsonld": "https://wpnews.pro/news/my-mathematical-regression.jsonld"}}