MathDB
Problems
Contests
National and Regional Contests
India Contests
India EGMO TST
India EGMO 2024 TST
4
4
Part of
India EGMO 2024 TST
Problems
(1)
I am always bigger than my index double
Source: India EGMO TST 2024/4
12/31/2023
Let
N
≥
3
N \geq 3
N
≥
3
be an integer, and let
a
0
,
…
,
a
N
−
1
a_0, \dots, a_{N-1}
a
0
,
…
,
a
N
−
1
be pairwise distinct reals so that
a
i
≥
a
2
i
a_i \geq a_{2i}
a
i
≥
a
2
i
for all
i
i
i
(indices are taken
m
o
d
N
\bmod~ N
mod
N
). Find all possible
N
N
N
for which this is possible.Proposed by Sutanay Bhattacharya
algebra
number theory
Egmo tst