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 A290226 #5 Jul 24 2017 12:31:39 %S A290226 2,23,62,77,119,194,287,398 %N A290226 Numbers n such that A290223(n) = 2. %C A290226 This sequence is believed to be finite. a(9) > 10^5, if it exists. %e A290226 62 is in this sequence because 62 - (6+2)^2 = -2. Then -2 + (2)^2 = 2. %o A290226 (PARI) %o A290226 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 A290226 for(n=1,10^5,if(a(n)==2,print1(n,", "))) %Y A290226 Cf. A007953, A003132, A290223. %K A290226 nonn,base,fini,full %O A290226 1,1 %A A290226 _Derek Orr_, Jul 24 2017