Question

Trouble writing loops for 3n+1 problem. Anyone with a clue?

Answer 1

Let me try this code
fun(n)
while n > 1
show n
if n is odd then
set n = 3n + 1
else
set n = n / 2
endif
endwhile
show n

Answer 2

That works. If you like a recursive version, try with:

def fun(n):
print n
if n is 1: return
if n is odd: n = 3n + 1
else: n = n/2
fun(n)