Sum/product of consecutive numbers and other math shortcuts

If you have studied some of the old SAT questions at some point you may have gone through questions like –

4 consecutive numbers sum to 166. What is the product of the numbers? or…

3 consecutive even numbers sum to X. What is their product?

The way the tutors and the online tutorials show seems to always be to algebraically solve this – for example 4 consecutive numbers would solve x+x+1+x+2+x+3 = 166, collect terms and solve…

However there is another way that works for this and works for other similar problems.

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Purism price increase scheduled for end of June

If you have been thinking of buying the new Librem phone now may be the best time to do so! The price will be increasing $100 according to a recent posting on their blog. And what better way to celebrate independence day than a device independent of many of the major tech giants’ updates? You can even buy a Librem phone that is built in USA… at over double the cost, however.

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PyImageSearch Review

If you have been doing OpenCV or Python machine learning, you have most likely come across PyImageSearch. If you come across a sale for this service I would recommend trying it out if you are learning some machine learning. This past week they have run a free promo 7 day trial, which gave me an opportunity to browse these.

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Keeping a process running with a 3 line Bash script

While you are running a long running process, you may want to run it again if it stops or is watching some process that should be running all the time. At first look at this might seem best to…

  • Create some cron running a script that checks output of “ps aux | grep myprogram”, run it if it is not running.
  • Wrap some other Python script calling it and at the end wait and try running again.
  • Check in on the process and see what might be wrong. (Not great, if it is a process you want to be checking errors in you should be using Sentry anyway)
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Government publication shows practical ways you can prep for an EMP

Chances are you have seen a movie or book recently covering the topic of an EMP – an Electro-magnetic pulse from a faraway nuke that could cause outages and damage. While most of what you hear will either be dismissive of the possibility, or a horror story of years of electronic wasteland, the reality could be more in the middle and is something folks can prepare for, according to a US government publication linked in the documents section of the SHARES site.

The SHARES system is a HF long range ham radio service but there are several recommendations in the document that just about any civilian should be considering, not just radio maintainers and organizations:

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Mathematicians submit proof of Erdős Coloring Conjecture

Fifty years ago, several mathematicians at a dinner party were discussing graphs (points and lines, not chart graphs), and the generalization if you make the edges connecting a point (vertex) with another, able to connect multiple points. While working out the minimal number of colors in general, they found it to be an interesting problem, to test out and prove the next day… Well, that solution, to Erdős, Faber, and Lovász’ problem was delayed for years and years!

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