qSequence = tail qq where
  qq = 0: 1: 1: map g [3..] 
  g n = qq !! (n - qq !! (n-1)) + qq !! (n - qq !! (n-2))


*Main> (take 10 qSequence, qSequence !! (1000-1))
([1,1,2,3,3,4,5,5,6,6],502)
(0.00 secs, 525044 bytes)