Let Mk denote the move that increases the blue number by k+1 and the red number by k2+2. We show that for any k≥2, the move Mk can be replaced by moves involving only M0 and M1 in such a way that the total increase in the blue number is the same, but the red number increases by less than k2+2.
Case 1: k=2p+1 is odd. Then Mk increases the blue number by 2p+2 and the red number by (2p+1)2+2. Instead, p+1 moves of type M1 increase the blue number also by 2p+2, but the red number increases by 3(p+1). Since (2p+1)2+2>3(p+1), for all p≥1, we can replace Mk with p+1 moves of M1.
Case 2: k=2p is even. Then Mk increases the blue number by 2p+1, and the red number by (2p)2+2. Alternatively, p moves of M1 and one move of M0 increase the blue number by 2p+1 and the red number by 3p+2. Since (2p)2+2>3p+2, for all p≥1, we conclude that Mk can be replaced by p moves of M1 and one M0.
Moreover, observe that two moves of M0 can be replaced by one move of M1, with a smaller increase in the red number: 3 instead of 4.
Thus, using only M0 and M1, and minimizing the use of M0, yields the minimal red number. To make the blue number at least N, the best strategy is to use only moves of type M1 (which increase blue by 2 and red by 3), plus at most one M0 (if needed).
If N is even: we can use ⌊2N⌋ moves of M1, increasing red by 3⋅2N=23N.
If N is odd: we can use ⌈2N⌉ moves of M1 and one move of M0, leading to red increasing by 3⌊2N⌋+2.
Hence, the minimal possible value of the red number is N+⌊2N+1⌋.