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 A229728 #18 Nov 07 2024 06:17:48 %S A229728 3,2,0,9,9,1,2,3,0,0,7,2,8,1,5,7,6,7,8,6,2,9,7,4,9,4,8,1,7,7,9,9,0,5, %T A229728 1,5,8,7,4,8,5,9,2,1,2,4,2,5,1,8,3,4,4,9,4,8,7,4,5,8,6,0,0,5,8,4,6,1, %U A229728 0,2,4,6,4,1,6,2,4,2,4,0,2,0,4,0,6,6,7,6,7,1,2,1,5,1,4,1,0,8,8,7,0,9,4,2,8,4,6,6,9,1,5,8,3,8,7,5,2,2,6,9 %N A229728 Decimal expansion of the square of the constant A130834. %D A229728 Steven R. Finch, Mathematical Constants, Cambridge, 2003, p. 232. %F A229728 From _Amiram Eldar_, Jun 12 2023: (Start) %F A229728 Equals exp(4*G/Pi) = exp(4*A006752/A000796). %F A229728 Equals A097469^4. (End) %e A229728 3.209912300728157678629749481779905158748592124251834494874586... %t A229728 RealDigits[Exp[4*Catalan/Pi], 10, 120][[1]] (* _Amiram Eldar_, Jun 12 2023 *) %o A229728 (PARI) exp(4*Catalan/Pi) \\ _Charles R Greathouse IV_, Jul 15 2014 %Y A229728 Cf. A000796, A006752, A097469, A130834. %Y A229728 Cf. A007341, A212800, A334088, A335586, A340139, A340176, A340557, A340562, A341479. %K A229728 nonn,cons %O A229728 1,1 %A A229728 _N. J. A. Sloane_, Oct 01 2013