a1 = first term = 4
a2 = second term = a1+5 = 4+5 = 0
a3 = third term a1 + 5 + 5 = a1 + 5(n-1), where n is the subscript that represents which term we're discussing.
an=4+5(n-1).
Is this correct? Let's check it and find out.
What is your prediction for a2? Here, n = 2. Then a2 = 4+5(2-1), or 4+5, or 9. That agrees with the given sequence rule.
Thus, the 250th term would be 4+5(250-1). Evaluate this, please.