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 A378827 #6 Dec 10 2024 05:50:54 %S A378827 2,3,7,9,0,4,4,9,1,4,8,3,8,8,1,0,6,8,1,7,1,9,5,3,7,2,9,1,1,6,4,6,2,0, %T A378827 0,6,6,1,2,8,0,3,0,2,3,5,6,8,8,5,5,3,5,2,6,9,1,8,3,3,0,5,2,5,7,5,1,9, %U A378827 5,2,5,8,7,6,9,1,9,6,5,8,6,9,2,1,0,0,1,0,3,3 %N A378827 Decimal expansion of the dihedral angle, in radians, between any two adjacent faces in a pentagonal icositetrahedron. %C A378827 The pentagonal icositetrahedron is the dual polyhedron of the snub cube. %H A378827 Paolo Xausa, <a href="/A378827/b378827.txt">Table of n, a(n) for n = 1..10000</a> %H A378827 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentagonal_icositetrahedron">Pentagonal icositetrahedron</a>. %F A378827 Equals arccos(c), where c is the real root of 7*x^3 - x^2 - 3*x + 1. %e A378827 2.37904491483881068171953729116462006612803023... %t A378827 First[RealDigits[ArcCos[Root[7*#^3 - #^2 - 3*# + 1 &, 1]], 10, 100]] (* or *) %t A378827 First[RealDigits[First[PolyhedronData["PentagonalIcositetrahedron", "DihedralAngles"]], 10, 100]] %Y A378827 Cf. A378823 (surface area), A378824 (volume), A378825 (inradius), A378826 (midradius). %Y A378827 Cf. A377969 and A377970 (dihedral angles of a snub cube). %K A378827 nonn,cons,easy %O A378827 1,1 %A A378827 _Paolo Xausa_, Dec 10 2024