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 A386690 #9 Jul 31 2025 08:43:13 %S A386690 5,8,1,1,4,6,5,0,7,7,7,8,0,0,0,5,9,5,0,7,5,0,2,7,8,1,9,7,2,0,1,4,0,0, %T A386690 1,5,2,9,5,3,3,3,9,0,9,3,0,7,4,5,5,9,0,0,4,4,0,8,5,2,0,8,5,7,6,1,4,4, %U A386690 4,6,5,9,4,8,9,4,4,3,5,5,9,7,9,8,4,7,6,3,6,1 %N A386690 Decimal expansion of the surface area of a diminished rhombicosidodecahedron with unit edges. %C A386690 The diminished rhombicosidodecahedron is Johnson solid J_76. %C A386690 Also the surface area of a paragyrate diminished rhombicosidodecahedron, a metagyrate diminished rhombicosidodecahedron and a bigyrate diminished rhombicosidodecahedron (Johnson solids J_77, J_78 and J_79, respectively) with unit edges. %H A386690 Paolo Xausa, <a href="/A386690/b386690.txt">Table of n, a(n) for n = 2..10000</a> %H A386690 Wikipedia, <a href="https://en.wikipedia.org/wiki/Bigyrate_diminished_rhombicosidodecahedron">Bigyrate diminished rhombicosidodecahedron</a>. %H A386690 Wikipedia, <a href="https://en.wikipedia.org/wiki/Diminished_rhombicosidodecahedron">Diminished rhombicosidodecahedron</a>. %H A386690 Wikipedia, <a href="https://en.wikipedia.org/wiki/Metagyrate_diminished_rhombicosidodecahedron">Metagyrate diminished rhombicosidodecahedron</a>. %H A386690 Wikipedia, <a href="https://en.wikipedia.org/wiki/Paragyrate_diminished_rhombicosidodecahedron">Paragyrate diminished rhombicosidodecahedron</a>. %F A386690 Equals 25 + (15*sqrt(3) + 10*sqrt(5 + 2*sqrt(5)) + 11*sqrt(5*(5 + 2*sqrt(5))))/4 = 25 + (15*A002194 + 10*sqrt(5 + A010476) + 11*sqrt(5*(5 + A010476)))/4. %F A386690 Equals the largest root of 256*x^8 - 51200*x^7 + 4070400*x^6 - 162560000*x^5 + 3311844000*x^4 - 27184400000*x^3 - 92251037500*x^2 + 2593051875000*x - 8774179671875. %e A386690 58.11465077780005950750278197201400152953339093... %t A386690 First[RealDigits[25 + (15*Sqrt[3] + 10*Sqrt[#] + 11*Sqrt[5*#])/4 & [5 + Sqrt[20]], 10, 100]] (* or *) %t A386690 First[RealDigits[PolyhedronData["J76", "SurfaceArea"], 10, 100]] %Y A386690 Cf. A386689 (volume). %Y A386690 Cf. A002194, A010476, A344149, A386692, A386694. %K A386690 nonn,cons,easy %O A386690 2,1 %A A386690 _Paolo Xausa_, Jul 29 2025