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 A054012 #9 Oct 27 2023 22:00:46
%S A054012 2,1,1,2,2,3,1,3,1,2,3,2,2,1,2,4,2,5,4,1,3,1,2,5,1,1,5,2,3,4,2,3,3,6,
%T A054012 2,1,2,1,8,1,1,7,1,2,4,2,1,2,1,2,8,3,4,4,4,6,1,9,5,4,2,1,1,2,1,2,1,2,
%U A054012 4,2,5,2,4,1,2,2,3,5,8,1,2,4,1,2,2,3,7,5,3,2,2,2,6,2,4,4,1,3,1,2,1,2,6,5,1
%N A054012 Nonzero values of n read modulo (number of proper divisors of n).
%F A054012 a(n) = A054011(A054009(n)).
%p A054012 with(numtheory):
%p A054012 [seq(`if`(i mod (tau(i)-1) <> 0,i mod (tau(i)-1),print( )), i=2..220)];
%t A054012 Cases[Table[Mod[n,DivisorSigma[0,n]-1],{n,2,200}],Except[0]] (* _Harvey P. Dale_, Nov 12 2011 *)
%Y A054012 Cf. A000005, A032741, A054009, A054011.
%K A054012 nonn
%O A054012 1,1
%A A054012 _Asher Auel_, Jan 17 2000