aₙ = (n – 1)(n + 2), n = 1, 2, 3, ...
• For n = 1:
a₁ = (1 – 1)(1 + 2)
a₁ = 0 · 3
a₁ = 0
________
• For n = 2:
a₂ = (2 – 1)(2 + 2)
a₂ = 1 · 4
a₂ = 4
________
• For n = 3:
a₃ = (3 – 1)(3 + 2)
a₃ = 2 · 5
a₃ = 10
________
• For n = 4:
a₄ = (4 – 1)(4 + 2)
a₄ = 3 · 6
a₄ = 18
________
• For n = 5:
a₅ = (5 – 1)(5 + 2)
a₅ = 4 · 7
a₅ = 28
So, the first five terms of the sequence are
(0, 4, 10, 18, 28)
I hope this helps.=)
