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2023 ISL
N8
N8
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2023 ISL
Problems
(1)
hi arnov
Source: ISL 2023 N8
7/17/2024
Determine all functions
f
:
Z
>
0
→
Z
>
0
f\colon\mathbb{Z}_{>0}\to\mathbb{Z}_{>0}
f
:
Z
>
0
→
Z
>
0
such that, for all positive integers
a
a
a
and
b
b
b
,
f
b
f
(
a
)
(
a
+
1
)
=
(
a
+
1
)
f
(
b
)
.
f^{bf(a)}(a+1)=(a+1)f(b).
f
b
f
(
a
)
(
a
+
1
)
=
(
a
+
1
)
f
(
b
)
.
functional equation
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Integers