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Pi SymbolThe five trillionth bit of Pi is '0'

Between March 21, 1998, and August 21, 1998, twenty-five computers from six different countries set a new record for calculating specific bits of Pi. The previous record of this type was the calculation of the trillionth bit in September 1997, by Fabrice Bellard.

(Note, the twenty-five computers is only a small subset of the computers running PiHex -- most people arrived after all the ranges were assigned).

The calculation took a total of about 13,500 cpu hours, and was done using 'idle' time slices (time slices which no other program wants to make use of) under Windows 95 and Windows NT.

The answer, starting at the 4,999,999,999,997th bit of Pi:

0000 0111 1110 0100 0101 0111 0011 0011 1100 1100

   ^ Five trillionth bit of Pi

0111 1001 0000 1011 0101 1011 0101 1001 0111 1001

or in hexadecimal, starting at the same point:


Read the (non-technical) press release, written by Simon Fraser University's Media and Public Relations Office.

Steve Finch has written an article about the BBP formula, (upon which Bellard's formula, is based) and the algorithm of Bailey, Borwein, and Plouffe, which we use.

A good mathematical reference for this topic is the paper which introduced the world for the first time to this type of calculation, written by Bailey, Borwein, and Plouffe. Available in PDF (193K) and Postscript (182K).

All the output produced by PiHex is available for download in pkzipped format here (230K). Read the included readme file for an explanation of the format of the data.