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.




s35:{sum {?[(0=x mod 3) | 0=x mod 5;x;0]} each 1+til x - 1}
s35 each 10 100 1000 10000 1000000