Difficulty: Easy
Correct Answer: 1707
Explanation:
Given data
2, 7, 27, 107, 427, ?
Concept/Approach
Test a simple linear recurrence of the form an+1 = 4an − 1.
Step-by-step
2 × 4 − 1 = 77 × 4 − 1 = 2727 × 4 − 1 = 107107 × 4 − 1 = 427Next: 427 × 4 − 1 = 1708 − 1 = 1707
Verification
The rule holds for every transition; applying once more yields 1707.
Discussion & Comments