**a(n) counts different values of i^2+j^2+k^2 <= n^2 or number of distances from the origin to all integer points inside a sphere of radius n.**

*1, 2, 5, 9, 15, 23, 32, 43, 55, 70, 86, 103, 122, 143, 166, 190, 215, 243, 273, 304, 336*

*1 seqfan posts*

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

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