[seqfan] A111076
Tomasz Ordowski
tomaszordowski at gmail.com
Wed Nov 13 20:34:26 CET 2019
Hello SeqFans!
Let a(n) = A111076(n) : https://oeis.org/A111076
If p is an odd prime, then a(p)^{lambda(p)/2} = a(p)^{(p-1)/2} == -1 (mod
p).
Conjecture: If lambda(n) = phi(n), then a(n)^{lambda(n)/2} == -1 (mod n).
Maybe someone knows how to prove it?
Numbers m such that lambda(m) < phi(m) and a(m)^{lambda(m)/2} == -1 (mod m)
are 28, 33, 42, 57, 65, 76, 93, 99, 124, 126, 129, 138, 145, 171, 172, 177,
185, ...
Best regards,
Thomas
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