Yet another π formula

[Gerson W. Barbosa]

(11-24-2024 01:59 PM)Thomas Klemm Wrote:  Example

10 ENTER 7
GSB A

0.285398164

.5 +
4 ×

3.141592654


It takes about 1'24" to return the result.

Mine is slower: ~ 1'33"

I don’t feel like writing an HP-15C today, so only a manual result for the first five terms and respective correction term:

4*(1/2 + 1/3 - 1/15 + 1/35 - 1/63 + 1/99) - 1/(60 + 3/2 - 3/(60 + 19/2 - 60/(60 + 51/2 - 315/(60 + 99/2 - 1008/(60 + 163/2 - 2475/(60 + 243/2))))))

= 407726194688/129783278625 = 3.1415926535967