1 2 2 4 2 2 2 9
Special number is 4 with power 2. After detontaion we are left with the sequence [1, 2, 9] with sum 12.
1 4 4 2 8 9 1
Special number is 9 with power 3. After detontaion we are left with the sequence [1, 4] with sum 5. Since the 9 has only 1 neighbour from the right we remove just it (one number instead of 3).