217
75
1-7-21-46-85-141. Take the "first differences" between the numbers. 6, 14, 25, 39, 56. Take the SECOND differences. 8, 11, 14, 17. Ah. It looks like a sequence where the second difference is two. Continue the next number in the second difference list. It would be 17 + 3 = 20. Add that number to the last number in the first difference list. 56 + 20 = 76. And that's what you add to the last number in the original pattern to get the next number in it. 141 + 76 = 217.
46+47+48=141
31
31.
31
18
Eighteen(18)
The next number in the sequence is 48.
67
91