Question 614863
The first two terms, a[1] and a[2], are the base cases. The following terms of the sequence are defined in terms of previous terms of the sequence (recursive sequence).


So the first two terms are given in the problem statement:
a[1] = 2
a[2] = 5


The next term, a[3], is given by a[3-2] - 3 * a[3-1].
a[3] = a[3-2] - 3 * a[3-1]
= a[1] - 3 * a[2]
= 2 - (3*5)
= -13


Then a[4] is given in terms of a[4-2] and q[4-1]:
a[4] = a[4-2] - 3 * a[4-1]
= a[2] - 3 * a[3]
= 5 - (3 * -13)
= 44


Likewise, a[5] is given in terms of a[5-2] and a[5-1]:
a[5] = a[5-2] - 3 * a[5-1]
= a[3] - 3 * a[4]
= -13 - (3 * 44)
= -145


So the first five terms in the sequence are:  {2, 5, -13, 44, -145}