SQL & PL/SQL

Hi All,

i want to add previous numer with current numebr ,that total numer with current number and so on

ex:

first 0+1=1
1+1=2
2+1=3
3+2=5
5+3=8..

to be generated upto 21 .Please help on this

0 1 1 2 3 5 8 13 21

Regards,
MR