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 A320428 #46 Nov 24 2019 16:13:53 %S A320428 2,5,5,1,3,25,1,1,17,1,3,3,1,12,1,8,5,3,1,46,3,4,12,1,5,22,3,2,1,7,4, %T A320428 2,1,13,13,8,1,1,3,1,1,1,2,1,11,1,5,2,1,4,7,1,71,1,1,1,6,1,1,1,1,1,1, %U A320428 1,4,6,1,9,1,1,1,6,1,1,1,5,1,1,1,5,1,1,1,1,1,2,2,1,1,5,2,1,2,10,1,19,2,2,4,1 %N A320428 Continued fraction expansion of exp(Pi/4). %C A320428 This value arises naturally by taking the ratio of the volume of a unit 2n-dimensional ball to the volume of the 2n-dimensional cube containing it (with side length 2) and summing over all n. %H A320428 Greg Egan, <a href="https://twitter.com/gregeganSF/status/1160461092973211648">Puzzle in which this value arises naturally</a> %H A320428 Grant Sanderson and Brady Haran, <a href="https://www.youtube.com/watch?v=6_yU9eJ0NxA">Darts in Higher Dimensions</a>, Numberphile video (2019) %t A320428 ContinuedFraction[Exp[Pi/4], 100] %o A320428 (PARI) contfrac(exp(Pi/4)) \\ _Felix Fröhlich_, Aug 28 2019 %Y A320428 Cf. A160510 (decimal expansion), A058287, A087299, A329912 (Engel expansion). %K A320428 nonn,cofr,easy %O A320428 0,1 %A A320428 _Grant T Sanderson_, Aug 28 2019