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 A063188 #11 Jan 02 2022 21:05:26
%S A063188 1,6,8,13,19,21,105,401,1053,2012,4310,114743,235156,287799,1269345,
%T A063188 1481217,1978865,2703836,3103386,3325474,18167905,553255504,782224772,
%U A063188 1039603284,26121336847,37996375306,60661762577,109713190320
%N A063188 Engel expansion of Sum_{k>=0} 1/(5 + k)^k.
%C A063188 Shgz(5) = 1.1891909643804311990212726717131587411...
%t A063188 ToEngel[ x_, n_Integer ] := Rest@First@Transpose@NestList[ {Ceiling[ 1/# ], #}&[ Times@@#-1 ]&, {1, Abs[ x ]+1}, n ]
%Y A063188 Cf. A006784 for definition of Engel expansion.
%K A063188 nonn,easy,nice
%O A063188 1,2
%A A063188 _Olivier Gérard_, Jul 10 2001