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 A020775 #35 Aug 04 2025 08:56:47 %S A020775 2,3,5,7,0,2,2,6,0,3,9,5,5,1,5,8,4,1,4,6,6,9,4,8,1,2,0,7,0,1,6,1,6,3, %T A020775 4,6,4,2,8,2,7,8,6,4,5,8,9,6,1,5,8,0,1,2,1,9,6,1,1,3,2,8,9,6,6,5,1,2, %U A020775 2,0,7,9,7,4,3,6,8,4,5,0,6,4,7,5,0,6,4,5,8,9,0,5,4,6,0,6,9,2,8 %N A020775 Decimal expansion of 1/sqrt(18). %C A020775 With offset 1, this is the decimal expansion of the volume of a cuboctahedron with edge length 1, which equals 5*sqrt(2)/3 = 2.357... . - _Wesley Ivan Hurt_, May 07 2021 %C A020775 Volume of a square pyramid and triangular bipyramid (Johnson solids J_1 and J_12, respectively) with unit edges. - _Paolo Xausa_, Aug 04 2025 %H A020775 Ivan Panchenko, <a href="/A020775/b020775.txt">Table of n, a(n) for n = 0..1000</a> %H A020775 Wikipedia, <a href="https://en.wikipedia.org/wiki/Cuboctahedron">Cuboctahedron</a>. %H A020775 Wikipedia, <a href="https://en.wikipedia.org/wiki/Square_pyramid">Square pyramid</a>. %H A020775 Wikipedia, <a href="https://en.wikipedia.org/wiki/Triangular_bipyramid">Triangular bipyramid</a>. %H A020775 <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>. %e A020775 0.2357022603955158414669481207016163464282786458961580121961132896... - _Vladimir Joseph Stephan Orlovsky_, May 30 2010 %t A020775 RealDigits[N[1/Sqrt[18],200]] (* _Vladimir Joseph Stephan Orlovsky_, May 30 2010 *) %Y A020775 Cf. A343199 (cuboctahedron surface area). %K A020775 nonn,cons,easy %O A020775 0,1 %A A020775 _N. J. A. Sloane_