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 A380705 #6 Jan 31 2025 04:21:08 %S A380705 2,0,1,1,7,2,1,8,9,8,7,8,5,4,1,1,8,2,8,5,8,8,6,1,4,6,9,6,5,5,8,2,9,1, %T A380705 7,1,3,7,3,6,9,4,4,8,2,7,8,6,4,9,0,7,5,6,4,8,0,6,1,3,2,3,1,5,4,3,0,5, %U A380705 6,3,4,0,6,6,8,3,7,6,2,1,5,9,5,1,9,0,7,0,8,4 %N A380705 Decimal expansion of the obtuse vertex angle, in radians, in a deltoidal icositetrahedron face. %H A380705 Paolo Xausa, <a href="/A380705/b380705.txt">Table of n, a(n) for n = 1..10000</a> %H A380705 Wikipedia, <a href="https://en.wikipedia.org/wiki/Deltoidal_icositetrahedron">Deltoidal icositetrahedron</a>. %F A380705 Equals arccos(-1/4 - sqrt(2)/8) = arccos(-1/4 - A020789). %F A380705 Equals 2*Pi - 3*A380704. %e A380705 2.0117218987854118285886146965582917137369448278649... %t A380705 First[RealDigits[ArcCos[-1/4 - Sqrt[2]/8], 10, 100]] %Y A380705 Cf. A380704 (face acute angles). %Y A380705 Cf. A020789, A378390, A378391, A378392, A378393, A378394. %K A380705 nonn,cons,easy %O A380705 1,1 %A A380705 _Paolo Xausa_, Jan 31 2025