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 A386465 #12 Jul 28 2025 10:53:58 %S A386465 1,0,2,1,8,2,0,9,2,2,2,0,2,1,3,9,1,8,5,7,7,9,8,8,5,4,2,4,5,2,8,1,5,3, %T A386465 3,2,0,5,2,9,8,4,2,1,5,9,5,3,6,1,4,3,6,8,9,9,8,1,3,2,6,8,5,2,1,3,9,0, %U A386465 7,1,9,0,7,8,1,5,0,3,9,6,6,7,2,0,5,9,0,9,3,2 %N A386465 Decimal expansion of the surface area of an augmented truncated dodecahedron with unit edges. %C A386465 The augmented truncated dodecahedron is Johnson solid J_68. %H A386465 Paolo Xausa, <a href="/A386465/b386465.txt">Table of n, a(n) for n = 3..10000</a> %H A386465 Wikipedia, <a href="https://en.wikipedia.org/wiki/Augmented_truncated_dodecahedron">Augmented truncated dodecahedron</a>. %F A386465 Equals (20 + 25*sqrt(3) + 110*sqrt(5 + 2*sqrt(5)) + sqrt(5*(5 + 2*sqrt(5))))/4 = (20 + 25*A002194 + 110*sqrt(5 + A010476) + sqrt(5*(5 + A010476)))/4. %F A386465 Equals the largest root of 256*x^8 - 10240*x^7 - 3955200*x^6 + 122240000*x^5 + 16152924000*x^4 - 343551280000*x^3 - 11461251137500*x^2 + 131995515375000*x + 634637481578125. %e A386465 102.18209222021391857798854245281533205298421595361... %t A386465 First[RealDigits[(20 + 25*Sqrt[3] + 110*Sqrt[#] + Sqrt[5*#])/4 & [5 + Sqrt[20]], 10, 100]] (* or *) %t A386465 First[RealDigits[PolyhedronData["J68", "SurfaceArea"], 10, 100]] %Y A386465 Cf. A386464 (volume). %Y A386465 Cf. A002194, A010476, A377694, A386412, A386460, A386543, A386545. %K A386465 nonn,cons,easy %O A386465 3,3 %A A386465 _Paolo Xausa_, Jul 25 2025