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 A378208 #10 Feb 11 2025 14:41:05 %S A378208 2,2,6,0,5,7,1,3,2,7,5,8,0,3,9,6,2,7,9,3,4,1,3,5,7,8,1,1,6,0,8,6,5,5, %T A378208 9,6,5,5,5,5,2,8,4,1,8,0,5,3,8,1,2,6,2,4,1,4,3,2,0,8,6,9,2,9,0,2,4,3, %U A378208 4,2,7,6,4,6,3,1,4,2,4,7,7,2,1,0,8,6,3,9,2,3 %N A378208 Decimal expansion of the dihedral angle, in radians, between any two adjacent faces in a triakis tetrahedron. %C A378208 The triakis tetrahedron is the dual polyhedron of the truncated tetrahedron. %H A378208 Wikipedia, <a href="https://en.wikipedia.org/wiki/Triakis_tetrahedron">Triakis tetrahedron</a>. %H A378208 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>. %F A378208 Equals arccos(-7/11). %e A378208 2.2605713275803962793413578116086559655552841805381... %t A378208 First[RealDigits[ArcCos[-7/11], 10, 100]] (* or *) %t A378208 First[RealDigits[First[PolyhedronData["TriakisTetrahedron", "DihedralAngles"]], 10, 100]] %Y A378208 Cf. A378204 (surface area), A378205 (volume), A378206 (inradius), A378207 (midradius). %Y A378208 Cf. A137914 and A156546 (dihedral angles of a truncated tetrahedron). %K A378208 nonn,cons,easy %O A378208 1,1 %A A378208 _Paolo Xausa_, Nov 21 2024