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 A308511 #17 Dec 10 2023 18:06:39
%S A308511 2,3,6,7,2,1,5,6,4,1,9,5,1,9,8,6,4,5,8,2,5,0,7,8,7,2,3,9,8,7,1,4,9,2,
%T A308511 1,7,1,9,5,1,9,7,1,1,2,9,7,7,2,6,3,2,5,3,6,2,0,0,3,9,1,5,6,5,4,2,8,6,
%U A308511 5,1,8,3,8,4,5,7,9,2,6,5,6,9,1,9,9,4
%N A308511 Decimal expansion of Sum_{k>=1} (k^(1/k^k) - 1).
%e A308511 0.236721564195198645825...
%p A308511 evalf(Sum(k^(1/k^k) - 1, k = 1..infinity), 120); # _Vaclav Kotesovec_, Jun 03 2019
%o A308511 (PARI) suminf(k=1, k^(1/k^k) - 1) \\ _Michel Marcus_, Jun 03 2019
%K A308511 nonn,cons
%O A308511 0,1
%A A308511 _Daniel Hoyt_, Jun 02 2019