Question

Determine the rule for the sequence:6;-4;6;1;6;6;6;11;6

Answer 1

Let the sequence be a₁, a₂, a₃, a₄, a₅, a₆, a₇, a₈, a₉, n = $(\overline{1,9})$

If n is odd, a_n = 6.

Otherwise, a_n = -4 + 5*($\frac{n}{2}$ -1)

According to these rules:

a₁ = 6

a₂ = -4 + 5*(1-1) = -4

a₃ = 6

a₄ = -4 + 5*(2-1) = 1

a₅ = 6

a₆ = -4 + 5*(3-1) = 6

a₇ = 6

a₈ = -4 + 5*(4-1) = 11

a₉ = 6