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 A172321 #33 Feb 18 2023 09:33:56
%S A172321 5,7,10,13,14,18,19,26,31,38,39,43,50,55,61,62,69,72,73,78,84,86,91,
%T A172321 95,96,98,103,108,109,110,115,119,122,123,129,133,136,138,139,145,146,
%U A172321 151,153,159,181,182,187,190,193,199,205
%N A172321 Duplicate of A154689.
%C A172321 Numbers n such that d(n)=d(n-d(n)).
%t A172321 sndQ[n_]:=Module[{dn=DivisorSigma[0,n]},dn==DivisorSigma[0,n-dn]]; Select[ Range[250],sndQ] (* _Harvey P. Dale_, Mar 05 2014 *)
%o A172321 (PARI) for(n=3,1000,if(numdiv(n)==numdiv(n-numdiv(n)),print1(n,", ")))
%K A172321 dead
%O A172321 1,1
%A A172321 _Juri-Stepan Gerasimov_, Nov 20 2010