In 1706, John Machin, secretary of England's Royal Society, developed a quickly converging formula for pi and used it to calculated the first 100 digits. In 1844, the idiot savant Johann Dase of Hamburg used Machin's formula to calculate 200 digits in less than two months.<ref>Beckmann</ref> In contrast, William Shanks spent twenty years calculating pi to 707 places, a task he completed in 1873. In 1945, it was discovered that only the first 527 of Shanks's digits were correct.
ENIAC, the first electronic computer, took seventy hours to calculate 2,037 digits in 1949. In 2008, the first million digits of pi were published on Project Gutenberg.<ref>Hemphill, Scott, ''[httphttps://www.gutenberg.org/ebooks/50 Pi to 1,000,000 places]''.</ref> In 2014, the anonymous programmer Houkouonchi calculated the first 13.3 trillion digits of pi in 208 days.<ref>Yee, Alexander, "[http://www.numberworld.org/y-cruncher/ y-cruncher - A Multi-Threaded Pi-Program]"</ref> This result has not been published.
==Pi in mathematics==
March 14 marks [[Pi Day]], a holiday on which the mathematical constant is celebrated. The date, 3/14, comes from the first three digits of pi. Some people begin their celebration at 1:59 pm, derived from the following three digits.
Pi Approximation Day is a similar holiday, celebrated on 22 July (from the approximation 22/7).<ref>[httphttps://www.usatoday.com/tech/science/mathscience/2007-03-14-pi-day_N.htm USA Today (3/14/2007) - Pi-day]</ref>
The value of pi is approximately: