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 A348909 #7 Nov 19 2021 08:12:38 %S A348909 1,6,5,8,9,6,7,0,8,1,9,1,6,9,9,4,0,7,9,3,4,6,7,7,5,1,5,6,7,8,4,0,1,5, %T A348909 6,1,5,2,4,3,9,9,3,3,4,4,5,6,2,7,7,7,1,0,0,3,5,2,2,1,5,4,8,8,9,8,4,1, %U A348909 6,8,0,2,0,7,8,0,3,3,6,0,7,4,8,4,4,2,9,0,7,8 %N A348909 Decimal expansion of the real root of x^3 + x^2 - 2*x - 4. %C A348909 This constant appears in the upper bounds formula of both the peak sidelobe level and the peak cross-correlation of Rudin-Shapiro sequences. %H A348909 Daniel J. Katz and Courtney M. van der Linden, <a href="https://arxiv.org/abs/2108.07318">Peak Sidelobe Level and Peak Crosscorrelation of Golay-Rudin-Shapiro Sequences</a>, arXiv:2108.07318 [cs.IT], 2021. See Theorems 1.3, 1.4 and 1.5, pp. 4-5. %F A348909 Equals ((44 + 3*sqrt(177))^(1/3) + (44 - 3*sqrt(177))^(1/3) - 1)/3. %e A348909 1.6589670819169940793467751567840... %t A348909 First[RealDigits[N[Root[x^3+x^2-2x-4,x,1],90]]] %o A348909 (PARI) solve(x=0, 2, x^3 + x^2 - 2*x - 4) \\ _Michel Marcus_, Nov 03 2021 %Y A348909 Cf. A020985, A020987, A348908. %K A348909 nonn,cons %O A348909 1,2 %A A348909 _Stefano Spezia_, Nov 03 2021