Find the wrong term in the following number series. 17 18 10 19 5 -20

The pattern is alternating additions and subtractions following a Fibonacci-like sequence: +1, -8, +9, -14, -25. The magnitudes 1, 8, 9, 14, 25 don't follow a clear pattern, but 5 breaks the expected flow as it should be a positive term around 26 (5+25=30, then alternating back to positive would give ~26). The term -20 follows correctly from 5-25, but 5 itself is the anomaly as it disrupts the alternating sign pattern.