A015990 - OEIS

%I #14 Dec 20 2018 15:42:13

%S 1397,1487,1577,1667,1757,1847,1937,2396,2486,2576,2666,2756,2846,

%T 2936,2999,3395,3485,3575,3665,3755,3845,3935,3998,4394,4484,4574,

%U 4664,4754,4844,4934,4997,5393,5483,5573,5663,5753,5843,5933,5996,6392,6482,6572,6662,6752,6842,6932,6995

%N Nine iterations of Reverse and Add are needed to reach a palindrome.

%C The number of iterations starts at 1, so palindromes (cf. A002113) are not excluded. The corresponding sequence excluding palindromes is A065214.

%H <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a>

%t 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 Cf. A002113.

%Y Different from A065214.

%K nonn,base

%O 1,1

%A _Robert G. Wilson v_

%E Corrected and extended by _Harvey P. Dale_, Mar 08 2015

%E Missing a(27)=4664 inserted by _Sean A. Irvine_, Dec 20 2018

%E Offset set to 1 by _Alois P. Heinz_, Dec 20 2018