Computer simulations ofn+-n-n+transferred-electron devices predict a frequency multiplier mode with favourable properties as a power source for the millimetre band. The mode is related to the l.s.a. ocillator, but waveform distortion allows operation to a considerably higher frequency. Second-harmonic generation is much more efficient than generation of higher harmonics. The dependence of the multiplier characteristics on carrier density, device length and frequency are analysed for two models of GaAs differing in the strength of the intervalley scattering rate. Comparison indicates that strong intervalley scattering leads to a higher frequency limit. Estimates of the power and impedance parameters of devices are made as precursors to circuit design.