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 A367409 #19 Dec 23 2023 14:43:28
%S A367409 1,0,1,8,6,5,6,3,5,1,6,7,4,0,5,1,3,6,7,3,6,6,2,2,9,9,2,5,2,5,2,7,5,4,
%T A367409 5,3,4,0,2,6,6,2,2,5,5,1,2,4,5,0,1,7,5,9,5,0,9,8,6,2,0,3,0,5,7,2,0,6,
%U A367409 3,0,7,5,2,3,7,7,8,9,5,9,9,6,6,9,8,1
%N A367409 Decimal expansion of arclength of (1 - 2^(1-x)) zeta(x), for 0 < x < 1.
%C A367409 See A367309.
%e A367409 1.0186563516740513673662299252527545340266...
%t A367409 f[x_] := (1 - 2^(1 - x)) Zeta[x]
%t A367409 y = NIntegrate[Sqrt[1 + f'[x]^2], {x, 0, 1}, WorkingPrecision -> 200]
%t A367409 RealDigits[y][[1]]
%o A367409 (PARI) f(x) = (1 - 2^(1-x))*zeta(x); intnum(x=0, 1, sqrt(1+f'(x)^2)) \\ _Michel Marcus_, Nov 27 2023
%Y A367409 Cf. A113024, A367309, A367311.
%K A367409 nonn,cons
%O A367409 1,4
%A A367409 _Clark Kimberling_, Nov 26 2023