Given explicit rule is:
f(n) = 1/2*n + 1
With an explicit rule, we can find any term by replacing n with that term.
For example,
when n = 1
f(n) = 1/2*n + 1
f(1) = 1/2 *1 + 1
f(1) = 1/2 + 1
f(1) = 3/2
n = 2
f(2) = 1/2 * 2 + 1
f(2) = 1 + 1
f(2) = 2
n = 3
f(3) = 1/2 * 3 + 1
f(3) = 3/2 + 1
f(3) = 5/2
n = 4
f(4) = 1/2 * 4 + 1
f(4) = 2 + 1
f(4) = 3
Hence, the first four terms are: 3/2, 2, 5/2, 3
