OFFSET
1,1
EXAMPLE
sigma(sigma(85) - phi(85)) = sigma(108 - 64) = 84; phi(sigma(85) + phi(85)) = phi(108 + 64) = 84, so 85 is a term of the sequence.
MATHEMATICA
r = {}; Do[d = DivisorSigma[1, n]; e = EulerPhi[n]; If[DivisorSigma[1, d - e] == EulerPhi[d + e], r = Append[r, n]], {n, 1, 10^5}]; r
CROSSREFS
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Sep 12 2002
EXTENSIONS
a(14)-a(33) from Donovan Johnson, Feb 17 2010
STATUS
approved