In a list of numbers, every number from the third one onwards is the sum of the two numbers immediately before it. The list begins 2, 5, 7, 12, 19, 31, … Which number stands in the 8th place?

Continue the rule: the 7th number is 19 + 31 = 50 and the 8th is 31 + 50 = 81. The traps: 50 is the 7th number, one place short; 131 is the 9th number, one place too far; and 62 comes from doubling 31 instead of adding the two numbers before it.