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 A337998 #8 Nov 03 2020 07:56:56
%S A337998 2,3,9,9,6,3,5,2,4,4,9,5,6,3,0,9,5,5,3,3,7,5,7,4,3,1,0,1,6,0,5,7,7,2,
%T A337998 2,5,8,9,7,8,6,4,4,3,6,8,0,1,7,7,0,0,4,2,6,6,7,6,2,8,9,3,7,4,5,0,0,8,
%U A337998 9,9,7,0,7,9,9,5,6,0,8,5,2,1,2,6,5,7
%N A337998 Decimal expansion of Sum_{n>=1} (cos((n*Pi)/2) + sin((n*Pi)/2)) / sqrt(n).
%F A337998 Equals zeta(1/2, 1/4).
%e A337998 0.2399635244956309553375743101605772258978644368017700426676289374...
%p A337998 evalf(Zeta(0, 1/2, 1/4)*10^86, 100):
%p A337998 ListTools:-Reverse(convert(floor(%), base, 10));
%t A337998 RealDigits[Zeta[1/2, 1/4], 10, 100][[1]] (* _Vaclav Kotesovec_, Nov 03 2020 *)
%Y A337998 zeta(1/2, 1/k): A059750 (k=1), A113024 (k=2), this sequence (k=4).
%K A337998 nonn,cons
%O A337998 0,1
%A A337998 _Peter Luschny_, Nov 03 2020