Wikipedia
The McNuggets version of the coin problem was introduced by Henri Picciotto,
who included it in his algebra textbook co-authored with Anita Wah. Picciotto
thought of the application in the 1980s while dining with his son at
McDonald's, working the problem out on a napkin. A McNugget number is
the total number of McDonald's Chicken McNuggets in any number of boxes.
In the United Kingdom, the original boxes (prior to the introduction of
the Happy Meal-sized nugget boxes) were of 6, 9, and 20 nuggets.

Task

Calculate (from 0 up to a limit of 100) the largest non-McNuggets
number (a number n which cannot be expressed with 6x + 9y + 20z = n
where x, y and z are natural numbers).




$possible = @{}
For ($i=0; $i -lt 18; $i++) {
  For ($j=0; $j -lt 13; $j++) {
    For ( $k=0; $k -lt 6; $k++ ) {
      $possible[ $i*6 + $j*9 + $k*20 ] = $true
    }
  }
}
 
For ( $n=100; $n -gt 0; $n-- ) {
  If ($possible[$n]) {
    Continue
  }
  Else {
    Break
  }
}
Write-Host "Maximum non-McNuggets number is $n"