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Romania Team Selection Test
2019 Romania Team Selection Test
1
number theory
number theory
Source:
February 2, 2017
number theory
algebra
Problem Statement
Let
k
≥
2
k\geq 2
k
≥
2
,
n
1
,
n
2
,
⋯
,
n
k
∈
N
+
n_1,n_2,\cdots ,n_k\in \mathbb{N}_+
n
1
,
n
2
,
⋯
,
n
k
∈
N
+
,satisfied
n
2
∣
2
n
1
−
1
,
n
3
∣
2
n
2
−
1
,
⋯
,
n
k
∣
2
n
k
−
1
−
1
,
n
1
∣
2
n
k
−
1
n_2|2^{n_1}-1,n_3|2^{n_2}-1,\cdots ,n_k|2^{n_{k-1}}-1,n_1|2^{n_k}-1
n
2
∣
2
n
1
−
1
,
n
3
∣
2
n
2
−
1
,
⋯
,
n
k
∣
2
n
k
−
1
−
1
,
n
1
∣
2
n
k
−
1
. Prove:
n
1
=
n
2
=
⋯
=
n
k
=
1
n_ 1=n_ 2=\cdots=n_k=1
n
1
=
n
2
=
⋯
=
n
k
=
1
.
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