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 A243955 #47 Feb 16 2025 08:33:22 %S A243955 12,79,761,761,761,761,761,36356642,1068822186 %N A243955 a(n) is the starting position of the first occurrence of a string of n 9's in the decimal expansion of 2*Pi. %C A243955 This sequence denotes the position of the Feynman point in the digits of tau = 2*Pi, from a(3) to a(7). Note how compared with A048940, tau has a Feynman point one digit longer, and one position lower, because at this point, the decimal expansion of Pi is 499999987, giving 99999997 when multiplied by 2. %H A243955 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FeynmanPoint.html">Feynman Point</a> %e A243955 The position of one consecutive 9 in 2*Pi=6.283185307179 is on the 12th decimal digit. %Y A243955 Cf. A048940 (similar, with Pi), A019692 (decimal expansion of 2*Pi). %K A243955 nonn,base %O A243955 1,1 %A A243955 _Jose Luis Garcia del Castillo_, Jun 19 2014 %E A243955 a(9) from _Chai Wah Wu_, Sep 30 2019