By the way, my understanding is that Simon Plouffe is 100% responsible for the so-called BBP formula.

From Math Reviews:

<< MR1479991 (98h:11166) 11Y60 Adamchik,Victor [Adamchik,V. S.]; Wagon, Stan (1-MACA) Asimple formula for . Amer.Math. Monthly 104 (1997), no. 9, 852–855. The authors show how to discover and prove formulas like the recent formula for given by D. H. Bailey, P. B. Borwein and S. Plouffe [Math. Comp. 66 (1997), no. 218, 903–913; MR1415794 (98d:11165)] which allows the computation of the nth base-16 digit of without knowing the previous digits. They use Mathematica to find a different but similar formula. Specifically, they use Mathematica to sum the series [a similar family of formulas goes here] and then determine the coefficients so that the sum is They then show how to give an integral equivalent formulation that eases the task of producing a verifiable proof. --Dan Rich wrote: << Simon Plouffe was one of the discoverers of the nice pi formula inf 4 2 1 1 -k pi = sum (---- - ---- - ---- - ----) 16 k=0 8k+1 8k+4 8k+5 8k+6 which allows computing individual bits of pi without computing the preceding part. It seems to me that there should be another such formula, in which the mod 8 residues are rearranged a little. Perhaps with 8k+3 and 8k+7 replacing 1 & 5, or maybe just 1&3 instead of 1&5, or with 8k+2 in place of 8k+6. Has anyone seen variations like this?

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