Mathematics for IGCSE & O level - Sequences (Section 4 - No. 7)
Which of the following sequences is an example of a quadratic sequence?
1, 3, 5, 7,...
2, 4, 6, 8,...
1, 4, 9, 16,...
3, 6, 12, 24,...
Explication
A quadratic sequence has a second common difference.