# How do you express the sequence below as a recursively defined function 4, 11, 25, 53, 109,...?

##### 1 Answer

Feb 11, 2017

Sequence as a recursively defined function is

#### Explanation:

Generally the functions are defined explicitly by a formula in terms of the variable, say

We can also define functions recursively: in terms of the same function of a smaller variable building on itself and in the case of sequences, this is generally the number of the term.

For example here, first term is

Observe that second term

and third term

Hence we can say

and

Hence we can say