JEE Main PAPER - 1

Let A be the sum of the first 20 terms and B be the sum of the first 40 terms of the series $1^{2} + 2 \cdot 2^{2} + 3^{2} + 2 \cdot 4^{2} + 5^{2} + 2 \cdot 6^{2} + \dots$  . If $B - 2A = 100\lambda$  , then $\lambda$   is equal to: