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.




(de sumMul (N F)
   (let N1 (/ (dec N) F)
      (*/ F N1 (inc N1) 2) ) )
 
(for I 20
   (let N (** 10 I)
      (println
         (-
            (+ (sumMul N 3) (sumMul N 5))
            (sumMul N 15) ) ) ) )