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 A386543 #14 Jul 28 2025 10:53:52 %S A386543 1,0,3,3,7,3,4,2,4,2,8,7,3,2,5,8,4,8,6,1,1,2,3,1,1,3,5,9,1,6,9,9,4,0, %T A386543 0,7,5,5,1,0,5,3,3,4,1,3,3,2,0,4,3,0,6,2,0,4,4,8,1,1,6,4,8,0,1,9,3,0, %U A386543 8,8,1,7,8,2,3,6,1,1,2,0,5,7,0,2,1,3,8,3,2,1 %N A386543 Decimal expansion of the surface area of a parabiaugmented truncated dodecahedron with unit edges. %C A386543 The parabiaugmented truncated dodecahedron is Johnson solid J_69. %C A386543 Also the surface area of a metabiaugmented truncated dodecahedron (Johnson solid J_70) with unit edges. %H A386543 Paolo Xausa, <a href="/A386543/b386543.txt">Table of n, a(n) for n = 3..10000</a> %H A386543 Wikipedia, <a href="https://en.wikipedia.org/wiki/Metabiaugmented_truncated_dodecahedron">Metabiaugmented truncated dodecahedron</a>. %H A386543 Wikipedia, <a href="https://en.wikipedia.org/wiki/Parabiaugmented_truncated_dodecahedron">Parabiaugmented truncated dodecahedron</a>. %F A386543 Equals (20 + 15*sqrt(3) + 50*sqrt(5 + 2*sqrt(5)) + sqrt(5*(5 + 2*sqrt(5))))/2 = (20 + 15*A002194 + 50*sqrt(5 + A010476) + sqrt(5*(5 + A010476)))/2. %F A386543 Equals the largest root of x^8 - 80*x^7 - 11400*x^6 + 796000*x^5 + 31475250*x^4 - 1804610000*x^3 - 8296459375*x^2 + 548931187500*x - 2544044046875. %e A386543 103.37342428732584861123113591699400755105334133204... %t A386543 First[RealDigits[(20 + 15*Sqrt[3] + 50*Sqrt[#] + Sqrt[5*#])/2 & [5 + Sqrt[20]], 10, 100]] (* or *) %t A386543 First[RealDigits[PolyhedronData["J69", "SurfaceArea"], 10, 100]] %Y A386543 Cf. A386466 (volume). %Y A386543 Cf. A002194, A010476, A377694, A385803, A386465, A386545. %K A386543 nonn,cons,easy %O A386543 3,3 %A A386543 _Paolo Xausa_, Jul 28 2025