A sequence is defined by a_n = (n + 1)!. What is its fourth term?

1. Substitute n = 4 into the formula: a_4 = (4 + 1)! = 5!. 2. Expand the factorial: 5! = 5 x 4 x 3 x 2 x 1 = 120. 3. Option B, 24, is 4!, which comes from forgetting to add 1 to n before taking the factorial. _Source: OpenStax Algebra and Trigonometry (CC BY 4.0), Ch 13 "Sequences, Probability and Counting Theory", section 13.1 SEQUENCES AND THEIR NOTATIONS_