How do you get the math pattern of 0 7 26 63 124 215?

Answer 1

There are infinitely many possible rules. It is easy to find a rule based on a polynomial of order 6 such that these six numbers are the first six values. There are also non-polynomial solutions. Short of reading the mind of the person who posed the question, there is no way of determining which of the infinitely many solutions is the "correct" one.

In this case, however, it is likely that the solution is

t(n) = n^3 - 1 for n = 1, 2, 3, ...