1.3 KiB
1.3 KiB
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f4831000cf542c50ff95 | Problem 278: Linear Combinations of Semiprimes | 5 | 301928 | problem-278-linear-combinations-of-semiprimes |
--description--
Given the values of integers 1 < a_1 < a_2 < \ldots < a_n
, consider the linear combination q_1a_1 + q_2a_2 + \ldots + q_na_n = b
, using only integer values q_k ≥ 0
.
Note that for a given set of a_k
, it may be that not all values of b
are possible. For instance, if a_1 = 5
and a_2 = 7
, there are no q_1 ≥ 0
and q_2 ≥ 0
such that b
could be 1, 2, 3, 4, 6, 8, 9, 11, 13, 16, 18 or 23.
In fact, 23 is the largest impossible value of b
for a_1 = 5
and a_2 = 7
. We therefore call f(5, 7) = 23
. Similarly, it can be shown that f(6, 10, 15)=29
and f(14, 22, 77) = 195
.
Find \sum f(pq,pr,qr)
, where p
, q
and r
are prime numbers and p < q < r < 5000
.
--hints--
linearCombinationOfSemiprimes()
should return 1228215747273908500
.
assert.strictEqual(linearCombinationOfSemiprimes(), 1228215747273908500);
--seed--
--seed-contents--
function linearCombinationOfSemiprimes() {
return true;
}
linearCombinationOfSemiprimes();
--solutions--
// solution required