13 17 23 29 31 37 ? ?

Solution: split the sequence into two interleaved subsequences (odd-position terms and even-position terms).

• Odd-position terms (1st, 3rd, 5th, ...): 13, 23, 31, ...

  Increments: 13 → 23 is +10, 23 → 31 is +8. The increment decreases by 2 each time, so the next increment is +6 and the next odd-position term is 31 + 6 = 37.

• Even-position terms (2nd, 4th, 6th, ...): 17, 29, 37, ...

  Increments: 17 → 29 is +12, 29 → 37 is +8. The increment decreases by 4 each time in this subsequence, so the next increment is +4 and the next even-position term is 37 + 4 = 41.

Therefore the two missing terms are 37 (7th term) and 41 (8th term).

If a single answer must be selected from the options provided, 41 is the correct choice because it is the 8th term produced by the pattern.