local fn IsPrime( n as NSUInteger ) as BOOL
  BOOL       isPrime = YES
  NSUInteger i

  if n < 2        then exit fn = NO
  if n = 2        then exit fn = YES
  if n mod 2 == 0 then exit fn = NO
  for i = 3 to int(n^.5) step 2
    if n mod i == 0 then exit fn = NO
  next
end fn = isPrime


local fn IsMotzkin
  NSUInteger M(42) : M(0) = 1 : M(1) = 1
  NSInteger  i, n

  printf @" 0.%20ld\n 1.%20ld", 1, 1
  for n = 2 to 41
    M(n) = M(n-1)
    for i = 0 to n-2
      M(n) += M(i) * M(n-2-i)
    next
    printf @"%2ld.%20ld\b", n, M(n)
    if fn IsPrime( M(n) ) then print " <-- is a prime" else print
  next
end fn

fn IsMotzkin

HandleEvents