Find the first six terms of the sequence in which f(1)=4 and f(n)=f(n-1)+(n+6), n>1

The first 6 terms are 4, 12, 21, 31, 42 and 54

Step-by-step explanation:

⇒ f(1) = 4

⇒ f(2) = f(1) + (2+6) = 4 + 8 = 12

⇒ f(3) = f(2) + (3+6) = 12 + 9 = 21

⇒ f(4) = f(3) + (4+6) = 21 + 10 = 31

⇒ f(5) = f(4) + (5+6) = 31 + 11 = 42

⇒ f(6) = f(5) + (6+6) = 42 + 12 = 54