Given:
[tex]c_n=n(n+1)[/tex]Required:
To find the first four terms of the sequence.
Explanation:
The first term is,
When n=1,
[tex]\begin{gathered} c_1=1(1+1) \\ =1\times2 \\ =2 \end{gathered}[/tex]When n=2,
[tex]\begin{gathered} c_2=2(2+1) \\ =2\times3 \\ =6 \end{gathered}[/tex]When n=3,
[tex]\begin{gathered} c_3=3(3+1) \\ =3\times4 \\ =12 \end{gathered}[/tex][tex]undefined[/tex]