lexicographicPermutations(699999) should return 1938246570.
    testString: assert(lexicographicPermutations(699999) == 1938246570, 'lexicographicPermutations(699999) should return 1938246570.');
  - text: lexicographicPermutations(899999) should return 2536987410.
    testString: assert(lexicographicPermutations(899999) == 2536987410, 'lexicographicPermutations(899999) should return 2536987410.');
  - text: lexicographicPermutations(900000) should return 2537014689.
    testString: assert(lexicographicPermutations(900000) == 2537014689, 'lexicographicPermutations(900000) should return 2537014689.');
  - text: lexicographicPermutations(999999) should return 2783915460.
    testString: assert(lexicographicPermutations(999999) == 2783915460, 'lexicographicPermutations(999999) should return 2783915460.');
```