15 lines
293 B
C++
15 lines
293 B
C++
#include <iostream>
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#include <cmath>
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using namespace std;
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int main(){
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// a1 = 1
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// an = 2(an-1 + 1)
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// an + 2 = 2(an-1 + 2)
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// an + 2 = 3*2^(n-1)
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// an = 3*2^(n-1) - 2
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int x;
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while (cin >> x){
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cout << 3*(long long)pow(2,x-1)-2 << endl;
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}
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return 0;
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} |