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1
n=q(q^2-q-1)=r(2r+1) for some primes q and r
n=q(q^2-q-1)=r(2r+1) for some primes q and r
Source: 2015 Belarus TST 5.1
November 5, 2020
number theory
primes
Problem Statement
Find all positive integers
n
n
n
such that
n
=
q
(
q
2
−
q
−
1
)
=
r
(
2
r
+
1
)
n=q(q^2-q-1)=r(2r+1)
n
=
q
(
q
2
−
q
−
1
)
=
r
(
2
r
+
1
)
for some primes
q
q
q
and
r
r
r
.B.Gilevich
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