For brevity denote F(n) by** F** and F(n-1) by **P**

Ans:

For **ODD** (the majority of Fibo series) values of F:

**F=P+P/P added (F-P) times +(P-P )added (p-1/2*(F+1)) times**

e.g. 13 =13+8/8 added (5) times+...(8-8)added (8-14/2) times

#OF TERMS=1+5*2+2*1=13

For EVEN(the rest of Fibo series) values of F:

**F=P+P-P/P repeated (2*P-F) times +(P-P )added 1/2*(3*F-4*P-2) times**

e.g. 34=21+21-21/21 **repeated** (8) times+...(21-21)added 1/2*(102-84-2) times

#OF TERMS=2+8*2+2*8=34

Works for any member except 1.

*Edited on ***July 10, 2010, 6:09 am**