Cullen numbers with the Lehmer property

Grau Ribas, José; Luca, Florian

doi:10.1090/S0002-9939-2011-10899-2

Cullen numbers with the Lehmer property
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by José María Grau Ribas and Florian Luca PDF

Proc. Amer. Math. Soc. 140 (2012), 129-134 Request permission

Corrigendum: Proc. Amer. Math. Soc. 141 (2013), 2941-2943.

Abstract:

Here, we show that there is no positive integer $n$ such that the $n$th Cullen number $C_n=n2^n+1$ has the property that it is composite but $\phi (C_n)\mid C_n-1$.

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