%I #16 Dec 29 2023 13:32:20
%S 12,297,539055,12949081200,167631138529627443759,
%T 888408727567955042239409874101472777521040,
%U 787659989217062162749912989661115208857840881836480202901460330472578518132645989056
%N a(1) = 12; for n >= 1, a(n+1) = abs((a(n) + R(a(n))) * (a(n) - R(a(n)))), where R(k) is the digit reversal of k.
%C The next term has 168 digits. - _Harvey P. Dale_, Dec 01 2017
%e a(2) = (12 + 21)*(21 - 12) = 297.
%t a = {12}; For[n = 2, n < 10,n++, AppendTo[a,Abs[(a[[ -1]] + FromDigits[Reverse[IntegerDigits[a[[ -1]]]]])* (a[[ -1]] - FromDigits[Reverse[IntegerDigits[a[[ -1]]]]])]]]; a (* _Stefan Steinerberger_, Jun 05 2007 *)
%t NestList[(#+IntegerReverse[#])Abs[#-IntegerReverse[#]]&,12,10] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 01 2017 *)
%K base,nonn
%O 1,1
%A _Amarnath Murthy_, Jul 09 2005
%E Corrected and extended by _Stefan Steinerberger_, Jun 05 2007
%E Definition corrected by _Georg Fischer_, Sep 09 2022