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2014 IMO Shortlist
A6
IMO Shortlist 2014 A6
IMO Shortlist 2014 A6
Source:
July 11, 2015
IMO Shortlist
algebra
functional equation
Problem Statement
Find all functions
f
:
Z
→
Z
f : \mathbb{Z} \to\mathbb{ Z}
f
:
Z
→
Z
such that
n
2
+
4
f
(
n
)
=
f
(
f
(
n
)
)
2
n^2+4f(n)=f(f(n))^2
n
2
+
4
f
(
n
)
=
f
(
f
(
n
)
)
2
for all
n
∈
Z
n\in \mathbb{Z}
n
∈
Z
.Proposed by Sahl Khan, UK
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