Kenneth Rosen Edition 7 Exercise 2.4 Question 7 (Page No. 168)

Question

Find at least three different sequences beginning with the terms $1, 2, 4$ whose terms are generated by a simple formula or rule.

Answer 1

FIRST SEQUENCE

$a_{n}=2^{n-1}$  where n=1,2,3,4......

SECOND SEQUENCE

$a_{n}=2a_{n-1},a_{1}=1$

THIRD SEQUENCE

$a_{n}=a_{n-1}+a_{n-2},a_{1}=1,a_{2}=2$