**Greatest common prime-divisor of sigma_1(n)=A000203(n) and sigma_2(n)=A001157(n); a(n)=1 if no common prime-divisor was found.**

*1, 1, 2, 7, 2, 2, 2, 5, 13, 2, 2, 7, 2, 2, 2, 31, 2, 13, 2, 7, 2, 2, 2, 5, 31, 2, 5, 7, 2, 2, 2, 7*

*1 seqfan posts*

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

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