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 A218006 #8 Mar 26 2013 14:37:56 %S A218006 1,34,36,96,128,468,1200,21216,102060,110976,117684,211428,331380, %T A218006 366660,437220,511680,530712,706560,710388,726240,732240,759360, %U A218006 838080,845376,875840,911040,975936,1014016,1041216,1093440,1110720,1141440,1167696,1289280 %N A218006 Numbers n such that sigma(tau(phi(n))) = tau(phi(sigma(n))) = phi(sigma(tau(n))). %C A218006 Here phi denotes Euler's totient function, tau(n) denotes number of divisors of n and sigma(n) denotes sum of all divisors of n. Only cyclic rotation of operators is considered. %t A218006 Select[Range[1000000], DivisorSigma[1, DivisorSigma[0, EulerPhi[#]]] == DivisorSigma[0, EulerPhi[DivisorSigma[1, #]]] == EulerPhi[DivisorSigma[1, DivisorSigma[0, #]]] &] %Y A218006 Cf. A000005, A000010, A000203, A033632, A076361, A078148. %K A218006 nonn %O A218006 1,2 %A A218006 _Jayanta Basu_, Mar 26 2013