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 A385805 #8 Jul 13 2025 07:13:32 %S A385805 2,1,9,7,9,4,8,7,1,3,3,6,8,3,9,9,2,1,5,5,5,5,9,0,3,1,5,7,7,1,4,4,5,0, %T A385805 7,7,7,0,7,0,1,8,8,7,2,3,1,8,8,0,7,1,2,3,1,8,0,7,3,1,2,8,5,3,6,1,5,9, %U A385805 5,6,9,7,4,3,2,8,8,6,9,6,2,2,1,0,4,6,2,6,9,3 %N A385805 Decimal expansion of the surface area of a triaugmented dodecahedron with unit edge. %C A385805 The triaugmented dodecahedron is Johnson solid J_61. %H A385805 Paolo Xausa, <a href="/A385805/b385805.txt">Table of n, a(n) for n = 2..10000</a> %H A385805 Wikipedia, <a href="https://en.wikipedia.org/wiki/Triaugmented_dodecahedron">Triaugmented dodecahedron</a>. %F A385805 Equals (3/4)*(5*sqrt(3) + 3*sqrt(5*(5 + 2*sqrt(5)))) = (3/4)*(5*A002194 + 3*sqrt(5*(5 + A010476))). %F A385805 Equals the largest root of 256*x^8 - 172800*x^6 + 26244000*x^4 - 1230187500*x^2 + 8303765625. %e A385805 21.97948713368399215555903157714450777070188723... %t A385805 First[RealDigits[3/4*(5*Sqrt[3] + 3*Sqrt[25 + 10*Sqrt[5]]), 10, 100]] (* or *) %t A385805 First[RealDigits[PolyhedronData["J61", "SurfaceArea"], 10, 100]] %Y A385805 Cf. A385804 (volume). %Y A385805 Cf. A002194, A010476, A385696, A385803. %K A385805 nonn,cons,easy %O A385805 2,1 %A A385805 _Paolo Xausa_, Jul 09 2025