What comes next and why 1 7 21 46 85 141?

Answer 1

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.