What is the missing number in the sequence 10 25 54 103?

Answer 1

The answer will depend on where in the sequence the missing number is:

Using only quartic polynomials, the solutions are:

3, 10, 25, 54, 103

10, 11.75, 25, 54, 103

10, 25, 33.8333..., 54, 103

10, 25, 54, 84.25, 103

10, 25, 54, 103, 178.

Other functional forms will generate many more answers.