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 A015990 #14 Dec 20 2018 15:42:13 %S A015990 1397,1487,1577,1667,1757,1847,1937,2396,2486,2576,2666,2756,2846, %T A015990 2936,2999,3395,3485,3575,3665,3755,3845,3935,3998,4394,4484,4574, %U A015990 4664,4754,4844,4934,4997,5393,5483,5573,5663,5753,5843,5933,5996,6392,6482,6572,6662,6752,6842,6932,6995 %N A015990 Nine iterations of Reverse and Add are needed to reach a palindrome. %C A015990 The number of iterations starts at 1, so palindromes (cf. A002113) are not excluded. The corresponding sequence excluding palindromes is A065214. %H A015990 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a> %t A015990 ra9Q[n_]:=Length[NestWhileList[#+FromDigits[Reverse[IntegerDigits[ #]]]&,n, IntegerDigits[ #]!= Reverse[IntegerDigits[#]]&,1,10]]==10; Select[ Range[ 7000],ra9Q] (* _Harvey P. Dale_, Mar 08 2015 *) %Y A015990 Cf. A002113. %Y A015990 Different from A065214. %K A015990 nonn,base %O A015990 1,1 %A A015990 _Robert G. Wilson v_ %E A015990 Corrected and extended by _Harvey P. Dale_, Mar 08 2015 %E A015990 Missing a(27)=4664 inserted by _Sean A. Irvine_, Dec 20 2018 %E A015990 Offset set to 1 by _Alois P. Heinz_, Dec 20 2018