923 B
923 B
id, title, challengeType, forumTopicId, dashedName
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5900f4c21000cf542c50ffd4 | Problem 340: Crazy Function | 5 | 301999 | problem-340-crazy-function |
--description--
For fixed integers a
, b
, c
, define the crazy function F(n)
as follows:
\begin{align} & F(n) = n - c \\;\text{ for all } n > b \\\\ & F(n) = F(a + F(a + F(a + F(a + n)))) \\;\text{ for all } n ≤ b. \end{align}
Also, define S(a, b, c) = \displaystyle\sum_{n = 0}^b F(n)
.
For example, if a = 50
, b = 2000
and c = 40
, then F(0) = 3240
and F(2000) = 2040
. Also, S(50, 2000, 40) = 5\\,204\\,240
.
Find the last 9 digits of S({21}^7, 7^{21}, {12}^7)
.
--hints--
crazyFunction()
should return 291504964
.
assert.strictEqual(crazyFunction(), 291504964);
--seed--
--seed-contents--
function crazyFunction() {
return true;
}
crazyFunction();
--solutions--
// solution required