**sigma_2(n): sum of squares of divisors of n.**

*1, 5, 10, 21, 26, 50, 50, 85, 91, 130, 122, 210, 170, 250, 260, 341, 290, 455, 362, 546*

*1 seqfan posts*

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

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