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National and Regional Contests
PEN Problems
PEN K Problems
28
28
Part of
PEN K Problems
Problems
(1)
K 28
Source:
5/25/2007
Find all surjective functions
f
:
N
→
N
f: \mathbb{N}\to \mathbb{N}
f
:
N
→
N
such that for all
n
∈
N
n\in \mathbb{N}
n
∈
N
:
f
(
n
)
≥
n
+
(
−
1
)
n
.
f(n) \ge n+(-1)^{n}.
f
(
n
)
≥
n
+
(
−
1
)
n
.
function
Functional Equations