OFFSET
1,2
COMMENTS
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.
MATHEMATICA
Select[Range[1000000], DivisorSigma[1, DivisorSigma[0, EulerPhi[#]]] == DivisorSigma[0, EulerPhi[DivisorSigma[1, #]]] == EulerPhi[DivisorSigma[1, DivisorSigma[0, #]]] &]
CROSSREFS
KEYWORD
nonn
AUTHOR
Jayanta Basu, Mar 26 2013
STATUS
approved