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 A033896 #17 Feb 03 2025 05:37:56
%S A033896 9,18,36,72,99,198,387,765,1332,2565,5121,6246,8712,9990,10989,12888,
%T A033896 25776,51453,64908,69597,126396,250065,252621,374877,722655,948222,
%U A033896 1170711,1281888,2410776,2535453,4870008,4874796,9342585,11688174,22834962,45069651
%N A033896 Sort then Add, a(1) =9.
%H A033896 Harvey P. Dale, <a href="/A033896/b033896.txt">Table of n, a(n) for n = 1..1000</a>
%p A033896 A033896 := proc(n)
%p A033896 option remember ;
%p A033896 if n =1 then
%p A033896 9;
%p A033896 else
%p A033896 A070196(procname(n-1)) ;
%p A033896 end if;
%p A033896 end proc:
%p A033896 seq(A033896(n),n=1..100) ; # _R. J. Mathar_, Feb 03 2025
%t A033896 NestList[FromDigits[Sort[IntegerDigits[#]]]+#&,9,40] (* _Harvey P. Dale_, Aug 19 2014 *)
%o A033896 (Python)
%o A033896 from itertools import accumulate
%o A033896 def sta(anm1, _): return anm1 + int("".join(sorted(str(anm1))))
%o A033896 print(list(accumulate([9]*36, sta))) # _Michael S. Branicky_, Sep 18 2021
%Y A033896 Cf. A033860, A066711.
%K A033896 nonn,base,easy
%O A033896 1,1
%A A033896 _N. J. A. Sloane_, _David W. Wilson_