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 A384284 #8 Aug 19 2025 12:09:34 %S A384284 2,5,2,4,0,0,0,3,7,9,0,8,3,2,5,8,3,5,1,3,7,3,1,2,7,8,0,5,1,8,9,2,5,8, %T A384284 6,4,5,2,8,1,6,6,6,2,3,6,5,1,6,9,5,5,8,3,2,2,1,5,3,7,7,8,9,5,4,5,3,5, %U A384284 6,0,8,5,6,9,1,2,6,6,9,3,7,5,9,2,2,6,0,8,9,2 %N A384284 Decimal expansion of the surface area of a gyroelongated pentagonal cupola with unit edge. %C A384284 The gyroelongated pentagonal cupola is Johnson solid J_24. %H A384284 Paolo Xausa, <a href="/A384284/b384284.txt">Table of n, a(n) for n = 2..10000</a> %H A384284 Wikipedia, <a href="https://en.wikipedia.org/wiki/Gyroelongated_pentagonal_cupola">Gyroelongated pentagonal cupola</a>. %H A384284 <a href="/index/Al#algebraic_08">Index entries for algebraic numbers, degree 8</a> %F A384284 Equals (20 + 25*sqrt(3) + sqrt(725 + 310*sqrt(5)))/4 = (20 + 25*A002194 + sqrt(725 + 310*A002163))/4. %F A384284 Equals the largest root of 256*x^8 - 10240*x^7 + 12800*x^6 + 3200000*x^5 - 22476000*x^4 - 203280000*x^3 + 1412362500*x^2 + 3080375000*x - 17984046875. %e A384284 25.240003790832583513731278051892586452816662365... %t A384284 First[RealDigits[(20 + 25*Sqrt[3] + Sqrt[725 + 310*Sqrt[5]])/4, 10, 100]] %t A384284 First[RealDigits[PolyhedronData["J24", "SurfaceArea"], 10, 100]] %o A384284 (PARI) (20 + 25*sqrt(3) + sqrt(725 + 310*sqrt(5)))/4 \\ _Charles R Greathouse IV_, Aug 19 2025 %Y A384284 Cf. A384283 (volume). %Y A384284 Cf. A002163, A002194, A179553, A179591, A179640, A384141. %K A384284 nonn,cons,easy %O A384284 2,1 %A A384284 _Paolo Xausa_, May 27 2025