Since you tell us you know \(\displaystyle a_6\), isn't it sort of trivial to compute \(\displaystyle a_6 ^2\) ? Can you explain in more detail please ?

Well \(\displaystyle a_6 ^2\) is the same as \(\displaystyle (a_6)^2\), so you basically just have to square the sixth term, yes.

But it seems too simple somehow. Are you sure the question didn't refer to \(\displaystyle a_{6^2}\) ? (this is equivalent to \(\displaystyle a_{36}\))

Well \(\displaystyle a_6 ^2\) is the same as \(\displaystyle (a_6)^2\), so you basically just have to square the sixth term, yes.

But it seems too simple somehow. Are you sure the question didn't refer to \(\displaystyle a_{6^2}\) ? (this is equivalent to \(\displaystyle a_{36}\))

Hey Bacterius,
Yes the question is just the power one (it's only one part of the question as a whole, so that's not the only thing asked!)
Thanks for your help!

EDIT : yep, I just saw that \(\displaystyle a_6\) was the square root of 3, which made it clear that the question asked \(\displaystyle a_6 ^2\). Thanks for replying though.