Sequence Guess

Guess the sequence. The solutions is near.

Sequence: 0 0 1 1 2 2 -9 -21 21 146 -144 -451 -2608

Solution
The solution is: 
-2608 20230
And the recurrence formula is 
seq[-1] - (seq[-2] * 5) -seq[-3] *seq[-4] +seq[-5] *seq[-6]
This fine program was brought to you by hakank@bonetmail.com
My other useless programs.