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 A270712 #17 Dec 01 2023 15:49:15 %S A270712 9,9,7,3,0,0,2,0,3,9,3,6,7,3,9,8,1,0,9,4,6,6,9,6,3,7,0,4,6,4,8,1,0,0, %T A270712 4,5,2,4,4,3,4,1,2,6,3,6,8,3,2,3,8,7,0,1,2,7,1,5,5,6,0,2,9,2,8,8,3,8, %U A270712 8,5,5,8,4,7,0,8,5,5,7,9,9,4,6,3,9,2,2 %N A270712 Decimal expansion of the fraction of the normal distribution that falls within the 3 sigma error bars. %H A270712 Wikipedia, <a href="http://en.wikipedia.org/wiki/68-95-99.7_rule">68-95-99.7 rule</a> %H A270712 Wikipedia, <a href="https://en.wikipedia.org/wiki/Normal_distribution">Normal distribution</a> %e A270712 0.997300203936739810946696370... %p A270712 erf(3/sqrt(2)) ; evalf(%) ; %t A270712 RealDigits[Erf[3/Sqrt[2]], 10, 120][[1]] (* _Amiram Eldar_, May 24 2023 *) %o A270712 (PARI) 1 - erfc(3/sqrt(2)) \\ _Michel Marcus_, Mar 22 2016 %Y A270712 Cf. A178647 (1sigma), A110894 (2sigma). %K A270712 nonn,cons %O A270712 0,1 %A A270712 _R. J. Mathar_, Mar 22 2016