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 A015986 #12 May 11 2025 17:22:58
%S A015986 188,190,197,287,296,386,395,485,494,584,593,683,692,782,791,881,890,
%T A015986 980,1394,1484,1574,1664,1754,1844,1898,1934,1988,1992,1994,1999,2393,
%U A015986 2483,2573,2663,2753,2843,2897,2933,2987,2991,2993,2998
%N A015986 Seven iterations of Reverse and Add are needed to reach a palindrome.
%C A015986 The number of iterations starts at 1, so palindromes (cf. A002113) are not excluded. The corresponding sequence excluding palindromes is A065212.
%H A015986 Harvey P. Dale, <a href="/A015986/b015986.txt">Table of n, a(n) for n = 0..1000</a>
%H A015986 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a>
%t A015986 sirapQ[n_]:=Boole[PalindromeQ/@Rest[NestList[#+IntegerReverse[#]&,n,7]]]=={0,0,0,0,0,0,1}; Select[Range[3000],sirapQ] (* _Harvey P. Dale_, May 11 2025 *)
%Y A015986 A002113, A065212.
%K A015986 nonn,base
%O A015986 0,1
%A A015986 _Robert G. Wilson v_