cp's OEIS Frontend

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.

A226118 Numbers n such that sigma(tau(phi(n))) = phi(tau(sigma(n))).

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%I A226118 #10 May 26 2016 12:19:42
%S A226118 1,2,136,160,170,204,240,282,716,745,1002,1077,1465,1509,1578,1868,
%T A226118 2012,2157,2346,2720,2760,3608,3898,4101,4461,4512,5066,5322,5898,
%U A226118 6189,7080,7185,7341,7628,7660,8108,8517,8665,8698,8709,8805,8922,8940,9234,9745,9962
%N A226118 Numbers n such that sigma(tau(phi(n))) = phi(tau(sigma(n))).
%H A226118 Paolo P. Lava, <a href="/A226118/b226118.txt">Table of n, a(n) for n = 1..1000</a>
%e A226118 For n=9962 we have:
%e A226118 sigma(9962)=15876 -> tau(15876)=45 -> phi(45)=24.
%e A226118 phi(9962)=4672 -> tau(4672)=14 -> sigma(14)=24.
%p A226118 with(numtheory); A226118:=proc(q) local n;
%p A226118 for n from 1 to q do
%p A226118 if sigma(tau(phi(n)))=phi(tau(sigma(n))) then print(n);
%p A226118 fi; od; end: A226118(10^6);
%t A226118 Select[Range[10000],EulerPhi[DivisorSigma[0,DivisorSigma[1,#]]] == DivisorSigma[ 1, DivisorSigma[ 0, EulerPhi[#]]]&] (* _Harvey P. Dale_, May 26 2016 *)
%Y A226118 Cf. A000005, A000010, A000203, A033632, A067160, A076361, A226117, A226119.
%K A226118 nonn
%O A226118 1,2
%A A226118 _Paolo P. Lava_, May 27 2013