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 A379136 #10 Feb 05 2025 10:31:12 %S A379136 2,7,3,5,2,5,4,7,6,1,4,9,0,3,3,4,6,6,1,9,8,9,8,5,6,0,1,8,3,9,3,4,9,5, %T A379136 7,9,2,7,1,6,9,6,9,3,3,9,6,5,5,6,8,5,7,4,2,9,3,0,4,0,0,5,9,0,1,3,0,2, %U A379136 9,3,0,5,7,6,0,6,9,2,0,0,0,3,1,1,4,6,4,5,3,8 %N A379136 Decimal expansion of the dihedral angle, in radians, between any two adjacent faces in a pentakis dodecahedron. %C A379136 The pentakis dodecahedron is the dual polyhedron of the truncated icosahedron. %H A379136 Paolo Xausa, <a href="/A379136/b379136.txt">Table of n, a(n) for n = 1..10000</a> %H A379136 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PentakisDodecahedron.html">Pentakis Dodecahedron</a>. %H A379136 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentakis_dodecahedron">Pentakis dodecahedron</a>. %F A379136 Equals arccos(-(80 + 9*sqrt(5))/109) = arccos(-(80 + 9*A002163)/109). %e A379136 2.7352547614903346619898560183934957927169693... %t A379136 First[RealDigits[ArcCos[-(80 + 9*Sqrt[5])/109], 10, 100]] (* or *) %t A379136 First[RealDigits[First[PolyhedronData["PentakisDodecahedron", "DihedralAngles"]], 10, 100]] %o A379136 (PARI) acos(-(80 + 9*sqrt(5))/109) \\ _Charles R Greathouse IV_, Feb 05 2025 %Y A379136 Cf. A379132 (surface area), A379133 (volume), A379134 (inradius), A379135 (midradius). %Y A379136 Cf. A236367 and A344075 (dihedral angles of a truncated icosahedron). %Y A379136 Cf. A002163. %K A379136 nonn,cons,easy %O A379136 1,1 %A A379136 _Paolo Xausa_, Dec 17 2024