Hi, thanks for the feedback. If you know the code for year x, you can quickly calculate the code for year x-1 or x+1. If you want to be able to quickly do this for any given year you would have to know the code for every year by heart. I just updated my blog post: Now it contains the year codes from 1800 to 2039. It also contains a small Go script that generates all these year codes and all you need to do if you want more year codes is to adjust the for-loop interval.
Hi, thanks for this question! On leap years the code for January and February is decreased by 1. Everything else stays the same! I updated the blog and the Go code to take care of this.