Notice that:
7=16-9
2=9-7
5=7-2
the next term would be: 2-5=-3
so each term of the sequence is equal to its previous term, subtracted from the second previous term:
Also, in order to describe the formula, we need to express the 2 first terms, 1 is not enough.
The recursive formula is:
[tex]a_1=16[/tex]
[tex]a_2=9[/tex]
[tex]a_n_2=a_n_1-a_n[/tex]
