How to turn a column vector into a line vector when the number was defined as a sequence?

You do that with the transpose operator, like you did.

But you have to do it on the vector, not on a range.

the vector is a, not an.

So remove that [n from a under the transpose and it works.

Explanation:

You created the vector a in a neat, regular, legal way, using the range n.

To show the vector a, all you need to do is type

a=

and it will show the column vector.

You typed

an=

which appears to show the same, but Prime interprets as something else. It takes the vector a, and apples the range n, and displays for each of the values of the range n, the corresponding element of a. And the displayed result looks just the same as when it shows the vector a.

Success!
Luc

According row vector:

According the green redefinition warning:

It appears because you are changing the value of "d". As this is exactly what you intend, you may ignore that warning.

You may also consider turning off these warnings