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 A378826 #7 Dec 10 2024 05:49:54 %S A378826 2,1,0,1,5,9,3,8,9,3,2,9,6,2,9,9,7,5,7,3,0,9,5,1,7,2,8,6,3,7,5,5,4,6, %T A378826 6,8,7,9,7,1,2,7,6,3,4,5,2,1,6,1,5,3,5,5,0,6,6,8,0,7,8,6,3,3,6,1,6,3, %U A378826 0,0,3,1,7,9,9,1,9,9,3,8,9,0,9,1,4,5,3,5,8,4 %N A378826 Decimal expansion of the midradius of a pentagonal icositetrahedron with unit shorter edge length. %C A378826 The pentagonal icositetrahedron is the dual polyhedron of the snub cube. %H A378826 Paolo Xausa, <a href="/A378826/b378826.txt">Table of n, a(n) for n = 1..10000</a> %F A378826 Equals (1 + s)/sqrt(2*(1 + s)*(1 - 2*s)), where s = (A058265 - 1)/2. %F A378826 Equals the positive real root of 32*x^6 - 144*x^4 + 12*x^2 - 1. %e A378826 2.101593893296299757309517286375546687971276345216... %t A378826 First[RealDigits[Root[32*#^6 - 144*#^4 + 12*#^2 - 1 &, 2], 10, 100]] (* or *) %t A378826 First[RealDigits[PolyhedronData["PentagonalIcositetrahedron", "Midradius"], 10, 100]] %Y A378826 Cf. A378823 (surface area), A378824 (volume), A378825 (inradius), A378827 (dihedral angle). %Y A378826 Cf. A377605 (midradius of a snub cube with unit edge length). %Y A378826 Cf. A058265. %K A378826 nonn,cons,easy %O A378826 1,1 %A A378826 _Paolo Xausa_, Dec 10 2024