To Find: First five terms of a given sequence.

Condition: n ≥ 2

Given: a₁ = 1, a_n = a_n–1 + 3 for n ≥ 2

Put n= 2 in n^th term (i.e. a_n), we have

a₂ = a_2–1 + 3 = a₁ + 3 = 1 + 3 = 4 (as a₁ = 1)

Put n= 3 in n^th term (i.e. a_n), we have

a₃ = a_3–1 + 3 = a₂ + 3 = 4 + 3 = 7 (as a₂ = 4)

Put n= 4 in n^th term (i.e. a_n), we have

a₄ = a_4–1 + 3 = a₃ + 3 = 7 + 3 = 10 (as a₃ = 7)

Put n= 5 in n^th term (i.e. a_n), we have

a₅ = a_5–1 + 3 = a₄ + 3 = 10 + 3 = 13 (as a₂ = 10)

First five terms of a given sequence is 1, 4, 7, 10, 13