886 B
886 B
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f49d1000cf542c50ffb0 | Problem 305: Reflexive Position | 5 | 301959 | problem-305-reflexive-position |
--description--
Let's call S the (infinite) string that is made by concatenating the consecutive positive integers (starting from 1) written down in base 10.
Thus, S = 1234567891011121314151617181920212223242...
It's easy to see that any number will show up an infinite number of times in S.
Let's call f(n) the starting position of the nth occurrence of n in S. For example, f(1)=1, f(5)=81, f(12)=271 and f(7780)=111111365.
Find ∑f(3k) for 1≤k≤13.
--hints--
euler305()
should return 18174995535140.
assert.strictEqual(euler305(), 18174995535140);
--seed--
--seed-contents--
function euler305() {
return true;
}
euler305();
--solutions--
// solution required