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 A209050 #18 Jun 28 2025 19:02:11 %S A209050 9,1,9,1,0,6,6,5,7,2,9,3,5,8,8,4,2,2,0,4,1,3,6,1,7,1,4,8,9,6,7,4,2,7, %T A209050 0,5,7,5,5,6,3,0,7,3,4,0,2,0,3,5,1,1,4,7,3,9,8,5,0,9,2,4,2,8,1,5,7,5, %U A209050 1,3,5,6,8,3,9,3,1,3,7,2,7,1,5,1,5,1,6,4,0,4,3,4,5,1,5,8,8,8,1,9,8,7,1,2,2,1,5,8,3,0,3 %N A209050 Pyramid angle = arccos(1/sqrt(e)) in radians. %F A209050 arccos(1/sqrt(e)) = arccos(1/sqrt(A001113)) = arccos(1/A019774) = arccos(A092605). %e A209050 = 0.91910665729358842204136171489674270575563073402035114... %e A209050 = 52°.660932385299557203750879574284228798519442622806897... %e A209050 = 52°39'.655943117973432225052774457053727911166557368413... %e A209050 = 52°39'39.3565870784059335031664674232236746699934421048..." %t A209050 RealDigits[ ArcCos[ 1/Sqrt[ E]], 10, 111][[1]] %o A209050 (PARI) acos(exp(-1/2)) \\ _Charles R Greathouse IV_, Mar 05 2012 %Y A209050 Cf. A001113, A019774, A092605. %K A209050 nonn,easy,cons %O A209050 0,1 %A A209050 _Robert G. Wilson v_, Mar 04 2012