Find patterns in numeric sequences quickly
Company: Optiver
Role: Software Engineer
Category: Statistics & Math
Difficulty: easy
Interview Round: Technical Screen
Solve pattern-finding sequence questions quickly without a calculator and explain the rule you detect for each: a) 3, 6, 12, 24, ? b) 2, 3, 5, 7, 11, ? c) 1, 4, 9, 16, ? d) 1, 2, 4, 7, 11, 16, ? If your first pass yields no clear pattern, state a skipping strategy and how you would return efficiently.
Overview: This question evaluates pattern recognition, numerical reasoning, and rapid logical deduction by asking for the next terms in both simple and irregular number sequences.
Read the full Optiver Software Engineer interview experience this question came from
Community answers
Answer by het1709
(a) 48. Each number is the double of the previous number.
(b) 13. This is the list of prime numbers.
(c) 25. Each number is the square of its index, starting from index=1.
(d) 22. The difference between each consecutive number increases by 1. The last difference was (16 - 11) = 5, so the next difference must be 6, giving (16 + 6) = 22.
Answer by wschang2003
48, 19, 25, 22
Answer by sxm1774
48, doubles each time
13, prime numbers
25, square numbers
22, difference increases by 1 each time