156371

Level 1
Yellow - 6n-3 - Lit up at 3, 9, 15 etc. Difference = 6, so 6n [first part], 3-6=-3 [second part]
Red - 9n-6 - Lit up at 3, 12, 21 etc. Same working as Y.
Blue - 11n-8 - Lit up at 3, 14, 25 etc. Ditto.
Green - 8n-5 - Lit up at 3, 11, 19 etc. Ditto.
Level 2
Yellow - 10n-5 - Lit up at 5, 15, 25 etc. Same working as Lvl 1 Y.
Red - n^2+n-2 - Lit up at 0, 4, 10, 18 etc. Difference is 4, 6, 8 etc and second difference is 2. Follows an^2+bn+c. For second difference, use 2a. For 1st difference, use 3a+b. For original sequence, use a+b+c. 2=2a, so a=1. 3a+b is 3+b=4, so b=1. 1+1+c=0, so c=-2
Blue - 3n-2 - Lit up at 1, 4, 7 etc. Same working as Lvl 1 Y.
Green - 3n^2-2n - Lit up at 1, 2, 5, 10 etc. Same working as R