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 A033657 #16 Jul 08 2025 19:55:00 %S A033657 23,55,110,121,242,484,968,1837,9218,17347,91718,173437,907808, %T A033657 1716517,8872688,17735476,85189247,159487405,664272356,1317544822, %U A033657 3602001953,7193004016,13297007933,47267087164 %N A033657 Trajectory of 23 under map x->x + (x-with-digits-reversed). %H A033657 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a> %F A033657 a(n) = A033655(n-1) = A033650(n+1), n>1. - _R. J. Mathar_, Oct 22 2008 %Y A033657 Cf. A033650, A033655. %K A033657 nonn,base %O A033657 0,1 %A A033657 _N. J. A. Sloane_