def fn.fib%(n%)
p1% = 0
p2% = 1
if n% = 0 then \
f% = 0 \
else \
for i% = 1 to n%
f% = p1% + p2%
p2% = p1%
p1% = f%
next i%
fn.fib% = f%
return
fend
print "First 20 Fibonacci numbers:"
for k% = 1 to 20
print fn.fib%(k%);
next k%
end