Problem C
Mynstursmisskilningur
Languages
en
is
Many students encounter proof by induction for the first time in the course Mathematical Structures for Computer Science. The teacher intended to set as homework the computation of the following sum
.
When
.
There was however a mishap when typing the problem and the sum ended up being
for quite a number of values of
Input
The first and only line of the input contains the integer
Output
Print the sum described above.
Sample Input 1 | Sample Output 1 |
---|---|
5 |
2650 |
Sample Input 2 | Sample Output 2 |
---|---|
20 |
530437386 |