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Putnam
1981 Putnam
A1
Putnam 1981 A1
Putnam 1981 A1
Source: Putnam 1981
March 31, 2022
Putnam
Convergence
Problem Statement
Let
E
(
n
)
E(n)
E
(
n
)
denote the largest integer
k
k
k
such that
5
k
5^k
5
k
divides
1
1
⋅
2
2
⋅
3
3
⋅
…
⋅
n
n
.
1^{1}\cdot 2^{2} \cdot 3^{3} \cdot \ldots \cdot n^{n}.
1
1
⋅
2
2
⋅
3
3
⋅
…
⋅
n
n
.
Calculate
lim
n
→
∞
E
(
n
)
n
2
.
\lim_{n\to \infty} \frac{E(n)}{n^2 }.
n
→
∞
lim
n
2
E
(
n
)
.
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