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 A385263 #7 Jun 30 2025 09:57:55 %S A385263 3,2,1,9,8,7,8,6,3,7,0,3,5,0,4,4,4,7,7,7,6,7,8,2,3,9,3,2,9,8,9,6,6,5, %T A385263 0,4,0,6,6,0,1,1,6,5,1,6,0,9,1,2,2,1,8,7,9,9,9,3,7,9,7,4,0,1,9,3,7,1, %U A385263 4,9,6,8,4,3,4,1,4,7,6,3,9,4,3,7,8,7,1,1,7,8 %N A385263 Decimal expansion of the surface area of a gyroelongated pentagonal cupolarotunda with unit edge. %C A385263 The gyroelongated pentagonal cupolarotunda is Johnson solid J_47. %H A385263 Paolo Xausa, <a href="/A385263/b385263.txt">Table of n, a(n) for n = 2..10000</a> %H A385263 Wikipedia, <a href="https://en.wikipedia.org/wiki/Gyroelongated_pentagonal_cupolarotunda">Gyroelongated pentagonal cupolarotunda</a>. %F A385263 Equals 5 + (35*sqrt(3) + 7*sqrt(25 + 10*sqrt(5)))/4 = 5 + (35*A002194 + 7*sqrt(25 + 10*A002163))/4. %F A385263 Equals the largest root of 256*x^8 - 10240*x^7 - 134400*x^6 + 7616000*x^5 - 756000*x^4 - 1373680000*x^3 + 2724312500*x^2 + 55840875000*x - 106054671875. %e A385263 32.198786370350444777678239329896650406601165160912... %t A385263 First[RealDigits[5 + (35*Sqrt[3] + 7*Sqrt[25 + 10*Sqrt[5]])/4, 10, 100]] (* or *) %t A385263 First[RealDigits[PolyhedronData["J47", "SurfaceArea"], 10, 100]] %Y A385263 Cf. A385262 (volume). %Y A385263 Cf. A002163, A002194, A384284, A385257, A385259, A385261. %K A385263 nonn,cons,easy %O A385263 2,1 %A A385263 _Paolo Xausa_, Jun 30 2025