fix: clean-up Project Euler 421-440 (#43047)

curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-427-n-sequences.md

@@ -8,24 +8,24 @@ dashedName: problem-427-n-sequences
 
 # --description--
 
-A sequence of integers S = {si} is called an n-sequence if it has n elements and each element si satisfies 1 ≤ si ≤ n. Thus there are nn distinct n-sequences in total.
+A sequence of integers $S = \\{s_i\\}$ is called an $n$-sequence if it has $n$ elements and each element $s_i$ satisfies $1 ≤ s_i ≤ n$. Thus there are $n^n$ distinct $n$-sequences in total.
 
-For example, the sequence S = {1, 5, 5, 10, 7, 7, 7, 2, 3, 7} is a 10-sequence.
+For example, the sequence $S = \\{1, 5, 5, 10, 7, 7, 7, 2, 3, 7\\}$ is a 10-sequence.
 
-For any sequence S, let L(S) be the length of the longest contiguous subsequence of S with the same value. For example, for the given sequence S above, L(S) = 3, because of the three consecutive 7's.
+For any sequence $S$, let $L(S)$ be the length of the longest contiguous subsequence of $S$ with the same value. For example, for the given sequence $S$ above, $L(S) = 3$, because of the three consecutive 7's.
 
-Let f(n) = ∑ L(S) for all n-sequences S.
+Let $f(n) = \sum L(S)$ for all $n$-sequences $S$.
 
-For example, f(3) = 45, f(7) = 1403689 and f(11) = 481496895121.
+For example, $f(3) = 45$, $f(7) = 1\\,403\\,689$ and $f(11) = 481\\,496\\,895\\,121$.
 
-Find f(7 500 000) mod 1 000 000 009.
+Find $f(7\\,500\\,000)\bmod 1\\,000\\,000\\,009$.
 
 # --hints--
 
-`euler427()` should return 97138867.
+`nSequences()` should return `97138867`.
 
 ```js
-assert.strictEqual(euler427(), 97138867);
+assert.strictEqual(nSequences(), 97138867);
 ```
 
 # --seed--
@@ -33,12 +33,12 @@ assert.strictEqual(euler427(), 97138867);
 ## --seed-contents--
 
 ```js
-function euler427() {
+function nSequences() {
 
   return true;
 }
 
-euler427();
+nSequences();
 ```
 
 # --solutions--