Find the first five terms of the sequence defined by each of these recurrence relations and initial conditions.
a) an = 6an-1, a0 = 2
b) an = a^2_n-1, a1 = 2
c) an = an-1 + 3an-2, a0 = 1, a1 = 2
d) an = nan-1 + n^2an-2, a0 = 1, a1 = 1
e) an = an-1 + an-3, a0 = 1, a1 = 2, a2 = 0