Journal of Integer Sequences, Vol. 20 (2017), Article 17.6.2

On the Equation σ(n) = n + φ(n)


Douglas E. Iannucci
Towers Condominiums B-16
3600 Contant
St. Thomas, VI 00802
USA

Abstract:

In this paper we consider the equation σ(n) = n + φ(n), for which n = 2 is the only known solution. We provide necessary conditions for the existence of any larger solutions.

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(Concerned with sequences A055940 A066679 A070159.)

Received January 9 2017; revised version received May 22 2017. Published in Journal of Integer Sequences, June 25 2017.

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