**Maximum k with 1 <= k <= n such that nk + 1 is prime (or 0 if no such prime exists).**

*1, 2, 2, 4, 2, 6, 6, 5, 8, 10, 8, 9, 12, 14, 14, 16, 14, 17, 12, 20, 20, 21, 20, 24, 24, 26*

*1 seqfan posts*

Index of A-numbers in seqfan: by ascending order by month by frequency by keyword

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