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 A290224 #4 Jul 24 2017 12:31:28 %S A290224 1,19,81,162,181,199,243,262,324,343,405,424,486,505,567,648,685,729, %T A290224 766,810,847,891,910,928,972,1053,1072,1134,1153,1215,1234,1296,1315, %U A290224 1377,1458,1495,1539,1576,1620,1657,1701,1720,1738,1782,1801,1819,1863,1944,1981,1999,2025,2044,2106,2125,2187,2206,2268 %N A290224 Numbers n such that A290223(n) = 0. %C A290224 This sequence is believed to be infinite. %e A290224 181 is in this sequence because 181 - (1+8+1)^2 = 81. Then 81 - (8+1)^2 = 0. %o A290224 (PARI) %o A290224 a(n)=k=n; c=1; v=List(); listput(v, k); while(c, if(k>=0, k-=sumdigits(k)^2; c+=1; if(k==2||k==3||k==0||k==6||k==9, return(k)); if(vecsearch(Vec(v), k), return(sumdigits(abs(k)))); listput(v, k)); if(k<0, k+=sumdigits(-k)^2; c+=1; if(k==2||k==3||k==0||k==6||k==9, return(k)); if(vecsearch(Vec(v), k), return(sumdigits(abs(k)))); listput(v, k)); c+=1) %o A290224 for(n=1,10^4,if(a(n)==0,print1(n,", "))) %Y A290224 Cf. A007953, A003132, A290223. %K A290224 nonn,base %O A290224 1,2 %A A290224 _Derek Orr_, Jul 24 2017