Answer:
(x * 3) + 1
Step-by-step explanation:
(1 * 3) + 1 = 4
(4 * 3) + 1 = 13
(13 * 3) + 1 = 40
etc
Answer:
the next number is 3 times of previous number + 1
Step-by-step explanation:
like;
[tex]4 = (1) \times 3 + 1[/tex]
[tex]13 = (4) \times 3 + 1[/tex]
etc...