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 A377277 #11 Nov 20 2024 23:40:55 %S A377277 1,1,4,6,3,7,9,9,4,1,7,4,9,4,1,1,1,3,3,7,9,6,6,2,8,5,2,3,0,1,8,9,0,9, %T A377277 3,0,5,0,9,2,0,9,7,6,3,4,0,1,2,0,0,6,5,8,9,1,5,1,6,3,7,7,5,5,1,8,6,2, %U A377277 9,4,4,5,5,0,8,4,7,7,1,7,4,6,4,6,4,8,6,9,9,2 %N A377277 Decimal expansion of 12*arctan(sqrt(2)). %C A377277 Dehn invariant of a truncated tetrahedron with unit edge and (negated) of a regular tetrahedron with unit edge. %H A377277 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DehnInvariant.html">Dehn Invariant</a>. %H A377277 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/RegularTetrahedron.html">Regular Tetrahedron</a>. %H A377277 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TruncatedTetrahedron.html">Truncated Tetrahedron</a>. %H A377277 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a> %F A377277 Equals 12*A195696 = A377296/2. %e A377277 11.463799417494111337966285230189093050920976340... %t A377277 First[RealDigits[12*ArcTan[Sqrt[2]], 10, 100]] (* or *) %t A377277 First[RealDigits[PolyhedronData["Tetrahedron", "DehnInvariant"], 10, 100]] %o A377277 (PARI) 12*atan(sqrt(2)) \\ _Charles R Greathouse IV_, Nov 20 2024 %Y A377277 Cf. A195696, A377296. %K A377277 nonn,cons,easy %O A377277 2,3 %A A377277 _Paolo Xausa_, Oct 23 2024