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 A384142 #8 May 23 2025 10:14:24 %S A384142 1,4,2,8,4,0,4,5,0,2,6,2,7,7,4,8,4,0,0,5,2,7,1,4,6,5,4,9,0,7,8,8,6,7, %T A384142 9,2,7,9,8,0,9,0,4,1,6,4,1,8,4,7,7,8,1,6,9,2,7,4,0,4,4,7,1,1,5,5,3,3, %U A384142 4,9,5,5,2,1,9,8,9,4,2,8,9,2,7,8,3,2,7,2,2,9 %N A384142 Decimal expansion of the volume of a gyroelongated square bipyramid with unit edge. %C A384142 The gyroelongated square bipyramid is Johnson solid J_17. %H A384142 Paolo Xausa, <a href="/A384142/b384142.txt">Table of n, a(n) for n = 1..10000</a> %H A384142 Wikipedia, <a href="https://en.wikipedia.org/wiki/Gyroelongated_square_bipyramid">Gyroelongated square bipyramid</a>. %F A384142 Equals (sqrt(2) + sqrt(4 + 3*sqrt(2)))/3 = (A002193 + sqrt(4 + A010474))/3. %F A384142 Equals the largest real root of 81*x^4 - 108*x^2 - 72*x-14. %e A384142 1.428404502627748400527146549078867927980904164... %t A384142 First[RealDigits[(Sqrt[2] + Sqrt[4 + Sqrt[18]])/3, 10, 100]] (* or *) %t A384142 First[RealDigits[PolyhedronData["J17", "Volume"], 10, 100]] %Y A384142 Cf. A010502 (surface area). %Y A384142 Cf. A002193, A010474, A179638. %K A384142 nonn,cons,easy %O A384142 1,2 %A A384142 _Paolo Xausa_, May 22 2025