Write a function compute_s_n
that for any given \(n\) computes the
sum \(S_n = 1^2 + 2^2 + 3^2 + \dots n^2\).
Define an empty numerical vector s_n
of size 25 using s_n <-
vector("numeric", 25)
and store in the results of
\(S_1, S_2, \dots S_{25}\) using a for-loop.