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 A329280 #15 Feb 16 2025 08:33:58
%S A329280 1,2,8,1,5,5,1,5,6,5,5,4,4,6,0,0,4,6,6,9,6,5,1,0,3,3,2,9,4,4,8,7,4,2,
%T A329280 8,1,8,6,1,9,9,0,7,8,2,4,3,5,2,5,8,2,6,5,9,7,0,2,6,4,8,2,3,0,5,6,5,7,
%U A329280 0,3,3,2,4,8,1,2,2,4,5,4,3,0,1,5,5,4,3,8,1,6,1
%N A329280 Decimal expansion of the quantile z_0.9 of the standard normal distribution.
%C A329280 z_p is the number z such that Phi(z) = p, where Phi(x) = Integral_{t=-oo..x} (1/sqrt(2*Pi))*exp(-t^2/2)*dt is the cumulative distribution function of the standard normal distribution. This sequence gives z_0.9 (also called the 9th decile or the 90th percentile).
%C A329280 This number can also be denoted as probit(0.9), where probit(p) is the inverse function of Phi(x). See the Wikipedia link below.
%H A329280 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/QuantileFunction.html">Quantile Function</a>
%H A329280 Wikipedia, <a href="https://en.wikipedia.org/wiki/Probit">Probit</a>
%F A329280 If X ~ N(0,1), then P(X<=1.2815515655...) = 0.9, P(X<=-1.2815515655...) = 0.1.
%t A329280 RealDigits[Sqrt[2] InverseErfc[9/10], 10, 100][[1]] (* _Jean-François Alcover_, Sep 26 2020 *)
%o A329280 (PARI) default(realprecision, 100); solve(x=0, 5, erfc(x)-2*0.1)*sqrt(2)
%Y A329280 Quantiles of the standard normal distribution: A092678 (z_0.75), this sequence (z_0.9), A329281 (z_0.95), A329282 (z_0.99), A329283 (z_0.995), A329284 (z_0.999), A329285 (z_0.9995), A329286 (z_0.9999), A329287 (z_0.99999), A329363 (z_0.999999).
%K A329280 nonn,cons
%O A329280 1,2
%A A329280 _Jianing Song_, Nov 12 2019