pub fn divisors_sum_table(size: usize) -> Vec<u64> {
let mut s = vec![0; size];
for i in (1..size).rev() {
for j in (i..size).step_by(i) {
s[j] += i as u64;
}
}
s
}
#[cfg(test)]
mod tests {
#[test]
fn test() {
use super::*;
assert_eq!(divisors_sum_table(10), [0, 1, 3, 4, 7, 6, 12, 8, 15, 13],);
}
}