Fibonacci number with "with recursive" in PostgreSQL

gistfile1.txt

with recursive r(a, b) as (
  select 0::int, 1::int
  union all
  select b, a + b from r where b < 1000
)
select a from r;

  a  
-----
   0
   1
   1
   2
   3
   5
   8
  13
  21
  34
  55
  89
 144
 233
 377
 610
 987
(17 rows)