Mathematics for IGCSE & O level - Sequences (Section 3 - No. 23)
Which of the following sequences has a constant *second* difference?
2, 5, 8, 11, ...
1, 3, 6, 10, ...
1, 4, 9, 16, ...
3, 6, 12, 24, ...
Explicación
A constant second difference characterizes a quadratic sequence.