## SUBJECT I

The sequence of numbers is given: $1,4,7,10,13,16,19$

a) Determine whether the 22nd term of the sequence is a perfect square.

b) Find the 2015th term of the sequence.
## SUBJECT I

a) If it is established that the general term has the form $T_{n}=3(n-1)+1$, then $\mathrm{T}_{22}=3(22-1)+1=64$ which is a perfect square.

4 p.

If the general term is not used and the enumeration is done explicitly, the 22nd term can be found and the $4 \mathrm{p}$ are awarded.
b) $\mathrm{T}_{2015}=3(2015-1)+1=6043$

$3 p$

Grading: a) $4 p$
b) $3 p$