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.




П1	0	П0	3	П4	ИП4	3	/	{x}	x#0
17	ИП4	5	/	{x}	x=0	21	ИП0	ИП4	+
П0	КИП4	ИП1	ИП4	-	x=0	05	ИП0	С/П