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MathsJEE Main 21 Jan 2026, Shift 1·Q22·Numerical·Tough

Sequences & Series · Recursive sequence and series sum

Let a1=1a_1 = 1 and for n≥1n \ge 1, an+1=12an+n2−2n−1n2(n+1)2a_{n+1} = \dfrac12 a_n + \dfrac{n^2 - 2n - 1}{n^2(n+1)^2}. Then ∣∑n=1∞(an−2n2)∣\left\lvert\displaystyle\sum_{n=1}^{\infty}\left(a_n - \frac{2}{n^2}\right)\right\rvert is equal to .

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