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Poland - First Round
1992 Poland - First Round
6
Sum in a recursive series in a sum
Sum in a recursive series in a sum
Source: Poland National Olympiad 1992 First Round #6
June 2, 2023
Problem Statement
The sequence
(
x
n
)
(x_n)
(
x
n
)
is determined by the conditions:
x
0
=
1992
,
x
n
=
−
1992
n
⋅
∑
k
=
0
n
−
1
x
k
x_0=1992,x_n=-\frac{1992}{n} \cdot \sum_{k=0}^{n-1} x_k
x
0
=
1992
,
x
n
=
−
n
1992
⋅
∑
k
=
0
n
−
1
x
k
for
n
≥
1
n \geq 1
n
≥
1
. Find
∑
n
=
0
1992
2
n
x
n
\sum_{n=0}^{1992} 2^nx_n
∑
n
=
0
1992
2
n
x
n
.
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