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3
Girls in Math at Yale 2021 Problem 3: Boring Sequence
Girls in Math at Yale 2021 Problem 3: Boring Sequence
Source:
February 27, 2021
Yale
college
Problem Statement
Suppose that
a
1
=
1
,
a_1 = 1,
a
1
=
1
,
a
2
=
2
a_2 = 2
a
2
=
2
, and for any
n
≥
3
n \ge 3
n
≥
3
,
a
n
=
a
1
+
a
2
+
⋯
+
a
n
−
1
a_n = a_1 + a_2 + \cdots + a_{n-1}
a
n
=
a
1
+
a
2
+
⋯
+
a
n
−
1
. Find
a
2021
a
2020
\frac{a_{2021}}{a_{2020}}
a
2020
a
2021
.Proposed by Andrew Wu
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