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 A342200 #14 Mar 08 2021 08:47:30
%S A342200 8,0,2,5,6,1,1,1,7,5,1,9,4,0,0,2,5,8,0,8,7,8,4,0,3,6,7,2,4,5,2,5,1,5,
%T A342200 9,5,6,5,0,0,6,4,6,6,5,6,3,7,1,0,4,3,7,7,4,7,0,8,4,4,9,8,0,3,8,4,5,8,
%U A342200 2,9,4,7,1,6,7,0,0,1,3,7,2,3,0,4,8,0,3,6,0,7,4,5,0,9,9,3,9,7,2,2,1,8,8,3,8,8
%N A342200 Decimal expansion of Product_{k>=1} (1/k)^(1/k^k).
%e A342200 0.802561117519...
%o A342200 (PARI) prodinf(k=1, (1/k)^(1/k^k)) \\ _Michel Marcus_, Mar 05 2021
%Y A342200 Cf. A342201.
%K A342200 nonn,cons
%O A342200 0,1
%A A342200 _Koksal Karakus_, Mar 04 2021
%E A342200 More digits from _Alois P. Heinz_, Mar 05 2021