Stoneham's series

[Johnh]

Thanks Albert, that's clever and insightful algebra wrangling, as are many of your posts!

I can see that the basic formula can never keep accuracy past about four decimal places, without an unusual number of calculation digits compared to many calculators. I might try it on Free42 with its 34 digits, just for fun, and to learn more about Free42.

But it works well enough to explore though, and I hadn't seen a method for Pi before like that, being based fully on products.