|
%I #20 Apr 06 2023 14:31:34
%S 1,7,8,15,28,56,24,60,24,56,56,120,60,168,168,63,56,120,96,252,104,
%T 112,168,480,63,252,234,360,195,336,104,210,224,360,224,248,168,480,
%U 360,546,252,728,224,504,480,336,224,504,186,255,336,260,360,1170,336,1170
%N a(n) = sigma(sigma(sigma(n))).
%C a(n) = A000203(A000203(A000203(n))) = A000203(A051027(n)) = A051027(A000203(n)). - _Jaroslav Krizek_, Jul 19 2009
%H Harry J. Smith, <a href="/A066971/b066971.txt">Table of n, a(n) for n = 1..1000</a>
%t lst={};Do[AppendTo[lst,DivisorSigma[1,DivisorSigma[1,DivisorSigma[1,n]]]],{n,5!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Mar 11 2009 *)
%t Table[Nest[DivisorSigma[1,#]&,n,3],{n,60}] (* _Harvey P. Dale_, Apr 06 2023 *)
%o (PARI) for(n=1,100,print1(sigma(sigma(sigma(n))),",")) \\ Lambert Klasen
%o (PARI) { for (n=1, 1000, write("b066971.txt", n, " ", sigma(sigma(sigma(n)))) ) } \\ _Harry J. Smith_, Apr 12 2010
%K nonn
%O 1,2
%A _Benoit Cloitre_, Jan 26 2002
|
