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.




(fold (lambda (x tot) (+ tot (if (or (zero? (remainder x 3)) (zero? (remainder x 5))) x 0))) 0 (iota 1000))