159. Sum of Squares 1..N
EasyFormula
Print 1² + 2² + … + n² modulo 10⁹ + 7.
Input format
A single integer n.
Output format
The sum mod 10⁹ + 7.
Example 1
Input
3
Output
14
Example 2
Input
1
Output
1
Constraints
1 ≤ n ≤ 10¹⁸
Read input from standard input and print the answer to standard output. Your code is judged against 4 test cases, most of them hidden.
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