Six nines in pi

A sequence of six consecutive nines occurs in the decimal representation of the number pi ( $π$ ), starting at the 762nd decimal place.^[1]^[2] It has become famous because of the mathematical coincidence, and because of the idea that one could memorize the digits of $π$ up to that point, and then suggest that $π$ is rational. The earliest known mention of this idea occurs in Douglas Hofstadter's 1985 book Metamagical Themas, where Hofstadter states^[3]^[4]

I myself once learned 380 digits of $π$ , when I was a crazy high-school kid. My never-attained ambition was to reach the spot, 762 digits out in the decimal expansion, where it goes "999999", so that I could recite it out loud, come to those six 9s, and then impishly say, "and so on!"

This sequence of six nines is colloquially known as the "Feynman point", after physicist Richard Feynman, who allegedly stated this same idea in a lecture.^[5] However it is not clear when, or even if, Feynman ever made such a statement. It is not mentioned in his memoirs and unknown to his biographer James Gleick.^[6]

^ Wells, D. (1986), The Penguin Dictionary of Curious and Interesting Numbers, Middlesex, England: Penguin Books, p. 51, ISBN 0-14-026149-4.
^ Sloane, N. J. A. (ed.). "Sequence A048940 (Starting position of the first occurrence of a string of at least n '9's in the decimal expansion of Pi)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
^ Hofstadter, Douglas (1985). Metamagical Themas. Basic Books. ISBN 0-465-04566-9.
^ Rucker, Rudy (5 May 1985). "Douglass Hofstadter's Pi in the Sky". The Washington Post. Archived from the original on 13 July 2017. Retrieved 4 January 2016.
^ Arndt, J. & Haenel, C. (2001). Pi – Unleashed. Translated by Lischka, Catriona & Lischka, David. Berlin: Springer. p. 3. ISBN 3-540-66572-2..
^ Brooks, David (12 January 2016). "Wikipedia turns 15 on Friday (citation needed)". Concord Monitor. Archived from the original on 18 January 2017. Retrieved 10 February 2016.

[Wells-1] Wells, D. (1986), The Penguin Dictionary of Curious and Interesting Numbers, Middlesex, England: Penguin Books, p. 51, ISBN 0-14-026149-4.

[2] Sloane, N. J. A. (ed.). "Sequence A048940 (Starting position of the first occurrence of a string of at least n '9's in the decimal expansion of Pi)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.

[metamagical-3] Hofstadter, Douglas (1985). Metamagical Themas. Basic Books. ISBN 0-465-04566-9.

[rucker-4] Rucker, Rudy (5 May 1985). "Douglass Hofstadter's Pi in the Sky". The Washington Post. Archived from the original on 13 July 2017. Retrieved 4 January 2016.

[ArndtHaenel-5] Arndt, J. & Haenel, C. (2001). Pi – Unleashed. Translated by Lischka, Catriona & Lischka, David. Berlin: Springer. p. 3. ISBN 3-540-66572-2..

[brooks-6] Brooks, David (12 January 2016). "Wikipedia turns 15 on Friday (citation needed)". Concord Monitor. Archived from the original on 18 January 2017. Retrieved 10 February 2016.

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