Or some other type of calculation in indexed set. I tried the maple android app with no luck. How is done in maple?

I want to find the formula for seq: 

För example 

{0,4,16,36,64,100,..}

{0,3,6,11,18,27.38,...}

How do i revers i backword fo get arithmetic sequence formula. I now the answare but want to learn how it's done in maple. I tried the app but i was not able to solve it. I have read the help and it looks like you have to use rsolve. Does anyboy has a sample to do not is trail and error. 

f := x -> 2*x/(x + 3)

p1 := plot(f(x), x = 0 .. 100);

p2 := with(plots);
inequal(58 < x, x = 0 .. 100, y = 0 .. 2);

display([p1, p2]);

Error, (in plots:-display) expecting plot structures but received:

How do i combine to p1 and p2 in the same graph. They print well individually..  Its maple 2021