1013 B
1013 B
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f5261000cf542c510038 | Problem 441: The inverse summation of coprime couples | 5 | 302113 | problem-441-the-inverse-summation-of-coprime-couples |
--description--
For an integer M
, we define R(M)
as the sum of \frac{1}{p·q}
for all the integer pairs p
and q
which satisfy all of these conditions:
1 ≤ p < q ≤ M
p + q ≥ M
p
andq
are coprime.
We also define S(N)
as the sum of R(i)
for 2 ≤ i ≤ N
.
We can verify that S(2) = R(2) = \frac{1}{2}
, S(10) ≈ 6.9147
and S(100) ≈ 58.2962
.
Find S({10}^7)
. Give your answer rounded to four decimal places.
--hints--
inverseSummationCoprimeCouples()
should return 5000088.8395
.
assert.strictEqual(inverseSummationCoprimeCouples(), 5000088.8395);
--seed--
--seed-contents--
function inverseSummationCoprimeCouples() {
return true;
}
inverseSummationCoprimeCouples();
--solutions--
// solution required