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 A339259 #12 Feb 07 2025 13:41:58 %S A339259 2,5,3,6,1,5,0,7,1,0,1,2,0,4,0,9,5,2,5,6,4,3,8,3,8,2,2,2,3,4,5,0,1,9, %T A339259 0,4,9,0,8,1,8,6,3,0,2,4,3,3,5,3,3,3,9,2,6,5,2,6,1,4,8,3,8,5,1,4,7,0, %U A339259 7,5,1,2,0,2,2,7,1,8,2,6,7,1,2,5,0,1,1 %N A339259 Decimal expansion of the volume of the regular icosahedron inscribed in the unit sphere. %H A339259 <a href="/index/Al#algebraic_04">Index entries for algebraic numbers, degree 4</a>. %F A339259 Equals 4*sqrt(2 + phi)/3 where phi = A001622. %F A339259 Equals A102208 / A019881 ^ 3. - _Amiram Eldar_, Jun 02 2023 %e A339259 2.536150710120409525643838222345019049081863024335333926526148385147... %t A339259 RealDigits[4 * Sqrt[GoldenRatio + 2]/3, 10, 120][[1]] (* _Amiram Eldar_, Jun 02 2023 *) %o A339259 (PARI) 4/3*sqrt(2+(1+sqrt(5))/2) %Y A339259 Cf. A001622, A019881, A102208. %Y A339259 Cf. A118273 (cube), A122553 (regular octahedron), A363437 (regular tetrahedron), A363438 (regular dodecahedron). %K A339259 nonn,cons %O A339259 1,1 %A A339259 _Hugo Pfoertner_, Nov 29 2020