Reflections on Valentin's 2023 Pi day special

[EdS2]

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What might I mean by an unfairly close value of Pi? Well, perhaps the successive record-breakers which get closer to Pi than their predecessors, or those which get much closer.

Have I written some BBC Basic? Yes, but only exploratory, not presently something to share. I'll post it if and when it feels ready. I'd always be interested in anyone else's efforts, of course, including yours, in an unaugmented Basic of your choice. (I think we still hope for a response from Eric.)

Indeed, you're right, I've been thinking of square free numbers, more than thinking of the Möbius function, and had missed the usefulness of its varying sign. I'd even spotted the same sum which runs up to root N, but the penny hadn't dropped. You made good use of both!

(In passing, I noted the term quadratfrei precisely because it wasn't in a German context, but in an English-language context. No need to tell me that there's no need to choose the word I choose to choose. I make the choicest choices, excepting only the exceptions.)