I'm agnostic on the validity of that proposed historical pi sequence for OEIS. But a foolish consistency had me recalling this one: https://oeis.org/A000053 <https://oeis.org/A000053> which I first heard as a math riddle from my father, who grew up in Brooklyn. —Dan
On May 22, 2016, at 9:56 PM, Neil Sloane <njasloane@gmail.com> wrote:
The proposed definition mentioned "Nth term is the year when pi was first calcuated to 10^N"
There are some obvious worries:
- why 10^n? why not 6^n? - who can be really sure which year something happened in? - why year? what calendar? why not "minute"? Is the instant when a computation was completed all that important? - do you really think 1400 is a(2) or a)3) or whatever?
The whole thing seems bogus, so I rejected it.
Best regards Neil
Neil J. A. Sloane, President, OEIS Foundation. 11 South Adelaide Avenue, Highland Park, NJ 08904, USA. Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ. Phone: 732 828 6098; home page: http://NeilSloane.com Email: njasloane@gmail.com
On Sun, May 22, 2016 at 11:10 PM, Keith F. Lynch <kfl@keithlynch.net> wrote:
1400, 1706, 1949, 1958, 1961, 1973, 1983, 1987, 1989, 1997, 1999, 2002, 2011
The Nth term is the year when pi was first calcuated to 10^N decimal places. 2011 is the 13th term because pi was calculated to ten trillion (10^13) places that year. Pi has not yet been calculated to 10^14 places.
Since 1949, the average time for each new factor of ten has been 6.2 years, a doubling every 1.9 years. I think it's a good illustration of the remarkable progress in computer hardware and software.
If this trend continues, one mole (Avogadro's number) of digits will be known before the 2080s.
I submitted it to OEIS, with references, but it was ruled "inappropriate."
I considered adding a zeroth term, -250, the approximate year when Archimedes first calculated pi. Others had *measured* pi to more than one decimal place long before his time, but he was the first person known to have *calculated* it.
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