This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A068079 #72 Mar 22 2025 06:36:36 %S A068079 3,1,4,1,5,9,2,9,2,0,3,5,3,9,8,2,3,0,0,8,8,4,9,5,5,7,5,2,2,1,2,3,8,9, %T A068079 3,8,0,5,3,0,9,7,3,4,5,1,3,2,7,4,3,3,6,2,8,3,1,8,5,8,4,0,7,0,7,9,6,4, %U A068079 6,0,1,7,6,9,9,1,1,5,0,4,4,2,4,7,7,8,7,6,1,0,6,1,9,4,6,9,0,2,6,5,4,8,6,7,2,5,6,6,3,7,1,6,8,1,4,1,5,9,2 %N A068079 Decimal expansion of 355 / 113. %C A068079 This is an approximation to Pi. It is accurate to 0.00000849%. %C A068079 355/113 is the third convergent of the continued fraction expansion of Pi (A001203). - _Lekraj Beedassy_, Jun 18 2003 %C A068079 In one of Ramanujan's papers, a note at the bottom states that "If the area of the circle be 140,000 square miles, then RD [RD = d/2 * Sqrt(355/113) = r*Sqrt(Pi), very nearly] is greater than the true length by about an inch." %C A068079 This approximation of Pi was suggested by the astronomer Tsu Chúng-chih (A.D. 430 - 501) (see Gullberg). - _Stefano Spezia_, Jan 13 2025 %D A068079 Calvin C. Clawson, Mathematical Mysteries, The Beauty and Magic of Numbers, Perseus Books, 1996, p. 88. %D A068079 John H. Conway and Richard K. Guy, The Book of Numbers, New York: Springer-Verlag, 1996. See pp. 187, 238-239. %D A068079 Jan Gullberg, Mathematics from the Birth of Numbers, W. W. Norton & Co., NY & London, 1997, §3.6 The Quest for Pi, p. 91. %D A068079 Ramanujan's papers, "Squaring the circle", Journal of the Indian Mathematical Society, V, 1913, 132. - _Robert G. Wilson v_, May 30 2014 %D A068079 David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, Revised edition 1987. See p. 49. %H A068079 Dario Castellanos, <a href="http://www.jstor.org/stable/2690037">The ubiquitous pi</a>, Math. Mag., 61 (1988), 67-98 and 148-163. [_N. J. A. Sloane_, Mar 24 2012] %H A068079 Dale, <a href="http://www.oocities.org/siliconvalley/pines/5945/facts.html">Fun and interesting facts about Pi</a>. %H A068079 <a href="/index/Ph#Pi314">Index entries for sequences related to the number Pi</a>. %H A068079 <a href="/index/Rec#order_57">Index entries for linear recurrences with constant coefficients</a>, signature (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1). %F A068079 a(n) = a(n - 112) for n > 113. - _Jeppe Stig Nielsen_, Dec 14 2019 %e A068079 3.141592920353982300884955752212389380530973451327433628318584... %p A068079 Digits:=100: evalf(355/113); # _Wesley Ivan Hurt_, Mar 14 2015 %t A068079 Flatten[RealDigits[355/113, 10, 100]] (* _Wesley Ivan Hurt_, Mar 14 2015 *) %o A068079 (PARI) 355/113. \\ _Charles R Greathouse IV_, May 30 2014 %o A068079 (PARI) a(n) = if(n==1, 3, digits(16*10^112 \ 113)[(n-2) % 112 + 1]) \\ _Jeppe Stig Nielsen_, Dec 14 2019 %Y A068079 Cf. A068028, A068089, A002485, A002486, A046965, A046947, A083871. %K A068079 easy,nonn,cons %O A068079 1,1 %A A068079 _Nenad Radakovic_, Mar 22 2002 %E A068079 More terms from _Sascha Kurz_, Mar 23 2002 %E A068079 Terms a(106) and beyond from _Jeppe Stig Nielsen_, Dec 14 2019