Answer
1: 1,2,4,7,11,16,22,....
2: 1,2,4,8,16,32,64,....
3: 1,2,4,13,....
Work Step by Step
1: the nth term could be obtained from the previous term
by adding n − 1
2: the geometry series,$2^n$
3: by the first three terms,we can construct the function
$x^3$+$ax^2$+$bx$+$c=f(x)$.
We can take 1,2,3 into the function,then we can get a,b,c.
So we have the next terms by taking 4,5,6...into this function.
