I've turned comments off on this blog as I'm getting quite a lot of spam. I've been able to keep on posting on flickr but haven't the time and energy to manage to be an active blogger. Sorry not to have been visiting your blogs.
My best wishes to you all!
Update: Comments are back on and I'm back!
BrainTwister #17: Semi-one numbers
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From New Scientist #3488, 27th April 2024 [link] When you count up to 2,
exactly half of the numbers contain the digit “1”. We can use the term
“semi-one n...