1,2

sigma(30)=phi(30) = 72-8 = 64 = 4^3, so 30 is a term of the sequence.

Select[Range[10^4], IntegerQ[(DivisorSigma[1, # ] - EulerPhi[ # ])^(1/3)] &]

Sequence in context: A050776 A090692 A102843 this_sequence A114944 A075290 A004222

Adjacent sequences: A062382 A062383 A062384 this_sequence A062386 A062387 A062388

nonn

Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Feb 13 2002