Question

3. The first four terms of a sequence are:

Answer 1

Step-by-step explanation:

tn=n(n+1)(2n+1)

t23=23(23+1)(2*23+1)

t23=36754

Answer 2

Answer:

The 23rd term is 2806.

Step-by-step explanation:

The other answerer has used the formula but i'm answering from the assumption that T1 to T4 are correct.

Each term is the sum of n terms of an arithmetic series with first term a1 = 12 and common difference d = 10.

Sum of n terms = (n/2)[2a1  + d(n - 1)]

So the sum of 23 terms =

= 23/2 (2*12 + 10 * 22)

= 11.5 * 244

= 2806.