Problem 12 from prior weeks.
Correct!
Explanation:
Solution: 71 comes next. This is the series of integers whose digits' sum is the distance to the next number in the series. The first two-digit integer, 10, has a digit sum of 1+0 = 1, so 1 is the distance to the first element of the series, 11. 11 has a digit sum of 1 + 1 = 2, so 11 + 2 = 13, whose digit sum 1 + 3 is 4, so 13 + 4 = 17, etc. The final number in the series shown above is 58, which has a digit sum 5 + 8 = 13, so the next number is 58 + 13 = 71.