Have a look at the sequences without the graphic for a better perspective:
Blue 3 and 4
Reason:
These are two separate sequences, blue and yellow, each with their own formulas.
All yellow are known.
4&5, 5&6
4&5, 5&6
Blues
1&2, 2&8
2&3, 4&6
3&4, 6&4
only the 9th square 3&4 had to be solved but if there was a 10th square it would be 6&4.
See the patterns now?
One only has to look and see.