Task

The objective is to write a function that finds the sum of all positive multiples of 3 or 5 below n.

Show output for n = 1000.

This is is the same as Project Euler problem 1.

Extra credit: do this efficiently for n = 1e20 or higher.




on sum35 (n)
  res = 0
  repeat with i = 0 to (n-1)
    if i mod 3=0 OR i mod 5=0 then
      res = res + i
    end if
  end repeat
  return res
end