Fibonacci sequence by recursive algorithm fail

[compsystems]

The Fibonacci sequence by recursive algorithm fail in program type CAS, why?

http://en.wikipedia.org/wiki/Fibonacci_number

HPPrime CAS CODE

Code:


#CAS
    fibo(n):=
    BEGIN
        // versión 0.0.1 April 20
            If n≤1 Then 
                    Return n;
            Else
                    Return (fibo(n-1)+fibo(n-2));
            End;
    END;
#end

fibo(16) → "Error: Bad argument count"

HPPrime NUM CODE

Code:

EXPORT fibo(n)
BEGIN
  // versión 0.0.1 April 20
    If n≤1 Then 
        Return n;
    Else
        Return (fibo(n-1)+fibo(n-2));
    End;
END;

fibo(16) → 987


TI68K CODE

Code:


fibo(n)
Func
  Local tm
  ©startTmr() → tm
  If n≤1 Then
      Return n
  Else
      Return fibo(n-1)+fibo(n-2)
      ©checkTmr( sc )
  EndIf
EndFunc

fibo(16) → 987

other algorithms

http://www.hpmuseum.org/forum/thread-316...=Fibonacci