There was a paper https://maa.org/sites/default/files/pdf/pubs/amm_supplements/Monthly_Reference_12.pdf https://maa.org/sites/default/files/pdf/pubs/amm_supple

There was a paper https://maa.org/sites/default/files/pdf/pubs/amm_supplements/Monthly_Reference_12.pdf https://maa.org/sites/default/files/pdf/pubs/amm_supplements... A Spigot Algorithm for the Digits of π Author(s): Stanley Rabinowitz and Stan Wagon Source: The American Mathematical Monthly, Vol. 102, No. 3 (Mar., 1995), pp. 195-203 Fortran code for the algorithm is at https://fortran-lang.discourse.group/t/fortran-code-snippets/2150/27 https://fortran-lang.discourse.group/t/fortran-code-snippets...