[seqfan] Re: Odd integers n such that Lucas(n) == 2 (mod n)

[Giovanni Resta]

The only thing I can say is a(4) = 237040185477.

Giovanni


Il 1 Ottobre 2019 11:18:38 CEST, Trizen <trizenx at gmail.com> ha scritto:
>Hello SeqFans,
>
>I would like to share a pretty strange sequence: odd integers n such
>that
>Lucas(n) == 2 (mod n), where Lucas(n) is the n-th Lucas number given by
>A000032(n).
>
>Equivalently: odd integers n such that A213060(n) = 2.
>
>The first three terms are: 1643, 387997, 174819237.
>
>It's quite surprising that these numbers are so rare.
>
>Some questions:
>- Is there anything known about this sequence?
>- In particular, is this sequence infinite?
>- Is it worth submitting to OEIS?
>
>Thank you,
>Daniel Suteu
>
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