18764번 - LCM Sum 다국어

문제

Are you sick of solving problems like computing the prefix sum of a random number theory function? As a terrible problem writer, here I present another one for you.

Compute

\[\sum_{x=1}^{n}{\text{lcm}(x, x+1, \dots, x+k)}\text{.}\]

The answer can be large, so output it modulo 10⁹ + 7.

입력

The first line contains two integers n, k (1 ≤ n ≤ 10¹⁸, 0 ≤ k ≤ 30).

출력

Output one integer: the answer.

제한

힌트