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 A033900 #12 Feb 03 2025 05:39:13 %S A033900 19,38,76,143,277,554,1009,1028,1156,2312,3535,6890,7579,13358,26716, %T A033900 39383,72772,95549,141148,252596,478165,623843,857311,970889,1049788, %U A033900 1197677,2365456,4711022,4823269,7057958,7615747,9072524,9297103,9420902 %N A033900 Sort then Add, a(1)=19. %p A033900 A033900 := proc(n) %p A033900 option remember ; %p A033900 if n =1 then %p A033900 19; %p A033900 else %p A033900 A070196(procname(n-1)) ; %p A033900 end if; %p A033900 end proc: %p A033900 seq(A033900(n),n=1..100) ; # _R. J. Mathar_, Feb 03 2025 %t A033900 NestList[#+FromDigits[Sort[IntegerDigits[#]]]&,19,40] (* _Harvey P. Dale_, Sep 02 2022 *) %Y A033900 Cf. A033860. %K A033900 nonn,base,easy %O A033900 1,1 %A A033900 _N. J. A. Sloane_, _David W. Wilson_