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 A163376 #13 May 04 2017 00:19:39 %S A163376 1,1,1,1,2,1,2,2,2,2,2,2,2,2,2,2,4,2,2,2,2,2,2,2,2,2,2,2,2,2,4,4,2,4, %T A163376 4,2,6,2,4,4,4,2,4,2,4,2,2,4,4,2,2,4,2,2,4,4,6,2,2,4,4,4,6,2,4,2,4,2, %U A163376 2,4,4,4,4,6,4,6,4,4,4,2,4,4,2,4,6,4,4,4,4,4 %N A163376 a(n) = phi(tau(phi(n))). %H A163376 G. C. Greubel, <a href="/A163376/b163376.txt">Table of n, a(n) for n = 1..1000</a> %F A163376 a(n) = A000010(A000005(A000010(n))) = A000010(A062821(n)) = A163109(A000010(n)). %p A163376 with(numtheory): A163376:=n->phi(tau(phi(n))): seq(A163376(n), n=1..200); # _Wesley Ivan Hurt_, May 03 2017 %t A163376 EulerPhi[DivisorSigma[0, EulerPhi[Range[100]]]] (* _G. C. Greubel_, Dec 20 2016 *) %o A163376 (PARI) vector(100, n, eulerphi(numdiv(eulerphi(n)))) \\ _G. C. Greubel_, Dec 20 2016 %Y A163376 Cf. A000005, A000010, A062821, A163109. %K A163376 nonn,easy %O A163376 1,5 %A A163376 _Jaroslav Krizek_, Jul 25 2009