What is the rule in these nunbers 3-7 4-10 5-13?

Answer 1

Let n (i) = the term number of each term in the sequence., with (i) going from 1-6 E.g term number 1 (n (1) ) is 3. n(2)= -7 etc...

Therefore n(i) for odd terms in the sequence is n (i)= (n (i -2)th term +1).

For even terms in the sequence, n(i)= (n (i - 2)th term -3).