**#{(i,j): mu(i)*mu(j) = -1, 1<=i<=n, 1<=j<=n}, where mu=A008683 (Moebius function).**

*0, 2, 4, 4, 6, 12, 16, 16, 16, 24, 30, 30, 36, 48, 60, 60, 70, 70, 80, 80, 96, 112, 126*

*1 seqfan posts*

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

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