Quadratic sequences - Sequences and Series

Notes:

The nth term of a quadratic sequence is always in the form
$an^{2}+bn+c$
Second common difference (2nd difference): the common difference of the common difference.
To find the nth term of the quadratic sequence, we need to find the values of a,b, and c. We find them using the three following formulas:
$a = \frac{(2^{nd} difference)}{2}$
$3a+b=2^{nd} term-1^{st} term$
$a+b+c=1^{st} term$
Isolate to solve for a,b and c and plug those values into the quadratic sequence. Then you will have the nth term!