13 lines
237 B
C++
13 lines
237 B
C++
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#include <bits/stdc++.h>
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const int N = 30;
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int a[N] = {2};
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using namespace std;
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int main() {
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int n;
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cin >> n;
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for (int i = 1; i <= n; ++i) a[i] = a[i - 1] + pow(2, i - 1);
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printf("%d", a[n]);
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return 0;
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}
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