[seqfan] Bold Conjecture about A290281

[Tomasz Ordowski]

Dear SeqFans,

I have a new Conjecture:

((n-1) mod phi(n)) = lambda(n) if and only if phi(n) + lambda(n) = n - 1.

Cf. A290281 : https://oeis.org/A290281 (see the last comment).

How to prove or disprove this conjecture?

Best regards,

Thomas Ordowski